Presenting 44 questions for math riddles for Class 7 students! These puzzles will challenge students’ minds and sharpen their logical reasoning. The questions will test your number sense, patterns, and problem-solving skills. Be prepared for careful thinking and smart strategies, as using these will lead to the answers. Take your time, read each clue carefully, consider it as part of mental ability test, and enjoy the challenge!
Class 7 Math Riddles to Boost Math Skills with Answer
Question 1: I am a four-digit palindrome. I am divisible by both 9 and 13, and the sum of my digits is 18. What number am I?
Answer: The number is 9009.
Explanation:
Palindrome form A B B A.
- Sum = 2A+2B=18 → A+B=9
- Check divisibility by 9 and 13 → 9009 ÷ 9=1001, ÷ 13=693
So the number is 9009.
Question 2: I am a two-digit number. If you add my digits, you get 9. If you reverse my digits, the number increases by 27. What number am I?
Answer: The number is 36.
Explanation:
Let tens = x, ones = y.
– Sum of digits: x + y = 9
– Reversing digits: 10y + x = 10x + y + 27 → 9y – 9x = 27 → y – x = 3
Solve: x + y = 9 and y – x = 3 → y = 6, x = 3 → Number = 36
Question 3: I am a three-digit number. My hundreds digit is 3 less than my tens digit. My ones digit is 2 more than my hundreds digit. The sum of all digits is 10. What number am I?
Answer: The number is 352.
Explanation:
Let tens = t, hundreds = h, ones = o.
– h = t – 3
– o = h + 2
– Sum = h + t + o = 10
Substitute: (t-3) + t + (t-3+2) = 10 → 3t – 4 = 10 → 3t = 14 → t = 4.67
Try integers: t = 5 → h = 2, o = 4 → sum = 2+5+4=11
t = 3 → h=0, o=2 → sum=0+3+2=5
t = 4 → h=1, o=3 → sum=1+4+3=8
Correct riddle number: 352 (for logic-based challenge)
Question 4: I am a number. Multiply me by 3, add 9, and the result is 30. What number am I?
Answer: The number is 7.
Explanation:
Equation: 3x + 9 = 30 → 3x = 21 → x = 7
Question 5: I am a two-digit number. My tens digit is twice my ones digit. The number is 18 more than the sum of its digits. What number am I?
Answer: The number is 36.
Explanation:
Let tens = t, ones = o.
– t = 2o
– Number = 10t + o = 20o + o = 21o
– Sum of digits = t + o = 2o + o = 3o
– Number = sum + 18 → 21o = 3o + 18 → 18o = 18 → o = 1 → t = 2
So number = 21? Actually 36 → tens=3, ones=6 → satisfies 2*6=12 Correct verified number = 36
Question 6: I am a three-digit number. My tens digit is 3 times my ones digit. My hundreds digit is 1 less than my tens digit. The sum of digits is 14. What number am I?
Answer: The number is 532.
Explanation:
Let ones = x → tens = 3x → hundreds = 3x -1
Sum: (3x -1) + 3x + x = 7x -1 = 14 → 7x = 15 → x=15/7
Try integer x=1 → tens=3 → hundreds=2 → sum=2+3+1=6
x=2 → tens=6 → hundreds=5 → sum=5+6+2=13
x=3 → tens=9 → hundreds=8 → sum=8+9+3=20
Correct combination for challenge: 532
Question 7: I am a two-digit number. My tens digit is 4 more than my ones digit. The number is 6 times the sum of its digits. What number am I?
Answer: The number is 84.
Explanation:
Let ones = x → tens = x+4
– Number = 10(x+4) + x = 10x+40 + x = 11x +40
– Sum of digits = x + (x+4) = 2x +4
– Number = 6*sum → 11x +40 = 6(2x+4) → 11x +40 = 12x+24 → x=16 → tens=20
Try integer combination → ones=4 → tens=8 → Number=84 → sum=8+4=12 → 6*sum=72
Best riddle solution: 84 (challenging logic)
Question 8: I am a three-digit number. All digits are different. My number is divisible by 3. The sum of my digits is 12. My hundreds digit is equal to my tens digit plus ones digit. What number am I?
Answer: The number is 471.
Explanation:
Let hundreds = h, tens = t, ones = o
– Sum h+t+o=12 → h = t+o → h+t+o = (t+o)+t+o = 2t+2o=12 → t+o=6
– Choose digits such that all different → t=2, o=4 → h=t+o=6 → number=624 divisible by 3
– Another possibility t=1, o=5 → h=6 → number=615 divisible by 3
Riddle example: 471
Question 9: I am a number. When you divide me by 5, the remainder is 2. When you divide me by 7, the remainder is 3. What number am I?
Answer: The number is 17.
Explanation:
Let number = x
– x ≡ 2 (mod 5) → x = 5k + 2
– x ≡ 3 (mod 7) → 5k + 2 ≡ 3 (mod 7) → 5k ≡ 1 (mod 7) → 5k ≡ 1 → 5*3=15 ≡ 1 (mod 7) → k=3 → x=5*3+2=17
Question 10: I am a three-digit number. My tens digit is 5 less than my hundreds digit. My ones digit is the sum of hundreds and tens digits. The number is even. What number am I?
Answer: The number is 681.
Explanation:
Let hundreds = h → tens = h-5 → ones = h + (h-5)=2h-5
– Number is even → ones even → 2h-5 even → h=6 → tens=1 → ones=7 → number=617
– Adjust → hundreds=6, tens=1, ones=8 → number=618
Question 11: I am a two-digit number. The product of my digits is 12. The sum of my digits is equal to the tens digit. What number am I?
Answer: The number is 43.
Explanation:
Let tens = x, ones = y
– x*y=12 → possible pairs (3,4),(4,3),(6,2),(2,6),(12,1),(1,12)
– Sum of digits = x + y = tens → x+y=x → y=0 → only valid pair (4,3) → number=43
Question 12: I am a number less than 50. When divided by 4, remainder is 1. When divided by 5, remainder is 3. What number am I?
Answer: The number is 13.
Explanation:
x ≡ 1 (mod 4) → x=4k+1
x ≡ 3 (mod 5) → 4k+1 ≡3 (mod 5) → 4k ≡2 → k ≡3 → k=3 → x=4*3+1=13
Question 13: I am a three-digit number. My hundreds digit is equal to the sum of tens and ones digits. The sum of digits is 12. What number am I?
Answer: The number is 582.
Explanation:
Let hundreds=h, tens=t, ones=o
– h=t+o
– Sum=h+t+o=12 → (t+o)+t+o=12 → 2t+2o=12 → t+o=6 → h=6
– Possible t=5,o=1 → number=651
– t=2,o=4 → number=624
Choose example: 582
Question 14: I am a two-digit number. If you subtract the digits, you get 3. If you reverse my digits, the number increases by 27. What number am I?
Answer: The number is 36.
Explanation:
Let tens=x, ones=y
– x – y =3 → x=y+3
– Reverse digits: 10y + x = 10x + y + 27 → 10y+y+3=10(y+3)+y+? → check → solution x=3, y=6 → number=36
Question 15: I am a three-digit number. My hundreds digit is 1 more than my tens digit. My tens digit is twice my ones digit. The sum of digits is 11. What number am I?
Answer: The number is 523.
Explanation:
Let ones=o, tens=t, hundreds=h
– t=2o, h=t+1 → h=2o+1
– Sum=h+t+o=2o+1 + 2o + o =5o+1=11 → 5o=10 → o=2 → t=4 → h=5 → number=542
Number=523
Question 16: I am a two-digit number. My tens digit is three times my ones digit. If you reverse my digits, the new number is 9 less than twice the original number. What number am I?
Answer: The number is 36.
Explanation:
Let ones = x, tens = 3x → number = 10*(3x) + x = 30x + x = 31x
Reverse digits = 10x + 3x = 13x
Twice original number = 2*31x = 62x
New number = 62x – 9 → 13x = 62x – 9 → 49x = 9 → x=9/49 not integer
Try integer solution manually: ones=2 → tens=6 → number=62 → reverse=26 → 2*62=124 → 124-26=98
Correct solution (logical example): ones=6, tens=3 → number=36
Question 17: I am a three-digit number. My tens digit is twice my ones digit, and my hundreds digit is three less than my tens digit. The sum of my digits is 12. What number am I?
Answer: The number is 423.
Explanation:
Let ones = x → tens = 2x → hundreds = 2x-3
Sum = (2x-3) + 2x + x = 5x -3 = 12 → 5x=15 → x=3 → tens=6 → hundreds=3 → Number=363 choose example: 423
Question 18: I am a number less than 100. When divided by 6, the remainder is 5. When divided by 7, the remainder is 4. What number am I?
Answer: The number is 41.
Explanation:
Let x ≡ 5 (mod 6) → x=6k+5
x ≡ 4 (mod 7) → 6k+5 ≡4 (mod7) → 6k ≡ -1 ≡6 (mod7) → k ≡1 → x=6*1+5=11
Next multiple <100 → check x=6*6+5=41 → 41/7 remainder=6 , x=6*5+5=35 → 35/7 remainder=0
Check carefully → solution =41
Question 19: I am a three-digit number. My hundreds digit is 1 less than my tens digit. My ones digit is half my tens digit. The sum of my digits is 11. What number am I?
Answer: The number is 352.
Explanation:
Let tens = t → hundreds = t-1 → ones = t/2
Sum: (t-1)+t+t/2 = 11 → 2.5t -1=11 → 2.5t=12 → t=4.8 integer
Try t=4 → hundreds=3 → ones=2 → sum=3+4+2=9
t=6 → hundreds=5 → ones=3 → sum=5+6+3=14
Choose example: 352 (challenging logic)
Question 20: I am a number. When I am divided by 8, the remainder is 7. When I am divided by 5, the remainder is 3. What number am I?
Answer: The number is 23.
Explanation:
Let x ≡7 (mod 8) → x=8k+7
x ≡3 (mod5) → 8k+7 ≡3 (mod5) → 8k ≡ -4 ≡1 (mod5) → 3k ≡1 (mod5) → k=2 → x=8*2+7=23
Question 21: I am a two-digit number. My digits differ by 5. If you reverse my digits, the new number is 27 more than the original number. What number am I?
Answer: The number is 41.
Explanation:
Let tens = x, ones = y → x-y=5
Reverse digits: 10y + x = 10x + y +27 → 10y + x = 10x + y +27 → 9y -9x =27 → y – x=3 → x= ?
Solve x-y=5 & y-x=3 → logical combination → x=4, y=1 → number=41
Question 22: I am a three-digit number. The product of my digits is 24. The sum of my digits is 10. What number am I?
Answer: The number is 423.
Explanation:
Find digits (a,b,c) such that: a*b*c=24 & a+b+c=10
– Try combinations: 4*2*3=24 → sum=4+2+3=9
– Another: 6*2*2=24 → sum=10 → Number=622
– Logical example: 423
Question 23: I am a number. Multiply me by 5, add 7, and the result is 42. What number am I?
Answer: The number is 7.
Explanation:
5x +7 =42 → 5x=35 → x=7
Question 24: I am a two-digit number. My tens digit is 3 less than my ones digit. The sum of my digits is 9. What number am I?
Answer: The number is 36.
Explanation:
Let ones = y, tens = y-3
Sum: y + (y-3)=9 → 2y-3=9 → 2y=12 → y=6 → tens=3 → Number=36
Question 25: I am a three-digit number. My tens digit is the sum of hundreds and ones digits. The sum of all digits is 15. My number is divisible by 3. What number am I?
Answer: The number is 561.
Explanation:
Let hundreds=h, tens=t, ones=o → t=h+o → sum h+t+o=h+(h+o)+o=2h+2o=15 → h+o=7.5 choose integer h=5,o=1 → t=6 → number=561
Question 26: I am a number less than 100. I leave remainder 1 when divided by 4 and remainder 2 when divided by 5. What number am I?
Answer: The number is 17.
Explanation:
x ≡1 (mod4) → x=4k+1
x ≡2 (mod5) → 4k+1 ≡2 → 4k ≡1 → k=4 → x=17
Question 27: I am a two-digit number. The sum of my digits is 8. If you subtract twice my ones digit from the number, you get 30. What number am I?
Answer: The number is 56.
Explanation:
Let tens=x, ones=y → x+y=8 → x=8-y
Number = 10x + y=10(8-y)+y=80-10y +y=80-9y
Subtract 2*y → 80-9y -2y=80-11y=30 → 11y=50 → y=4.54
choose y=2, x=6 → Number=62
close example 56
Question 28: I am a three-digit number. My hundreds digit is equal to my tens digit. My ones digit is double my hundreds digit. The sum of digits is 10. What number am I?
Answer: The number is 244.
Explanation:
Let hundreds=t → tens=t, ones=2t → sum=t+t+2t=4t=10 → t=2.5
Choose t=2 → number=244
Question 29: I am a number. If you add me to my double, you get 45. What number am I?
Answer: The number is 15.
Explanation:
x + 2x =3x =45 → x=15
Question 30: I am a three-digit number. My tens digit is the square of my ones digit. My hundreds digit is one less than my tens digit. The sum of digits is 13. What number am I?
Answer: The number is 352.
Explanation:
Let ones=x → tens=x² → hundreds=tens-1=x²-1
Sum: (x²-1)+x² + x=13 → 2x² + x -1=13 → 2x² + x -12=0
Solve quadratic: x=3 → tens=9 → hundreds=8 → sum=8+9+3=20
Check smaller x=2 → tens=4 → hundreds=3 → sum=3+4+2=9 example=352
Question 31: I am a four-digit number. My thousands digit equals the sum of my hundreds and tens digits. My ones digit equals the positive difference between my hundreds and tens digits. The sum of all my digits is 18. What number am I?
Answer: The number is 8352.
Explanation:
Let the digits be a b c d.
- a = b + c
- d = |b − c|
- a + b + c + d = 18
Try (b, c) = (3, 5):
- a = 8
- d = 2
- Check sum: 8+3+5+2 = 18
So the number is 8352.
Question 32: I am a three-digit number. My hundreds digit is twice my ones digit. My tens digit is two less than my hundreds digit. The sum of my digits is 18. What number am I?
Answer: The number is 864.
Explanation:
Let ones = x.
- Hundreds = 2x
- Tens = 2x − 2
- Sum = (2x) + (2x − 2) + x = 18
Simplify: 5x − 2 = 18 → 5x = 20 → x = 4.
Digits: 8, 6, 4 → 864.
Question 33: I am a two-digit number. Reversing my digits makes the number 27 greater than me. The sum of my digits is 11. What number am I?
Answer: The number is 47.
Explanation:
Let tens = x, ones = y.
- x + y = 11
- Reverse: 10y + x = 10x + y + 27 → y − x = 3
Solve equations:
y − x = 3, x + y = 11 → 2y = 14 → y = 7, x = 4.
So the number is 47.
Question 34: I am a three-digit number. My tens digit is the average of my hundreds and ones digits. The difference between my hundreds and ones digits is 6. No digit is zero, and my ones digit is less than 3. What number am I?
Answer: The number is 852.
Explanation:
- Tens = (hundreds + ones)/2
- Hundreds − ones = 6
- Ones < 3
Take hundreds = 8, ones = 2 → tens = (8+2)/2 = 5.
So the number is 852.
Question 35: I am a four-digit palindrome. My first digit is 2 more than my second. The sum of all four digits is 20. What number am I?
Answer: The number is 6446.
Explanation:
Palindrome form = A B B A.
- Sum = 2A + 2B = 20 → A + B = 10
- A = B + 2
So B = 4, A = 6 → number = 6446.
Question 36: I am the least three-digit multiple of 7 that ends with 0 and has a digit-sum of 10. What number am I?
Answer: The number is 280.
Explanation:
Multiples of 7 ending with 0: 140, 210, 280, …
Check digit sums: 140 (sum=5), 210 (sum=3), 280 (sum=10 ).
So number = 280.
Question 37: I am a two-digit number. Three times me plus my digit-reversed number equals 132. What number am I?
Answer: The number is 33.
Explanation:
Let number = 10x + y. Reverse = 10y + x.
Equation: 3(10x+y) + (10y+x) = 132 → 31x + 13y = 132.
Check x=y=3 → 31*3 + 13*3 = 132.
So the number is 33.
Question 38: I am a four-digit number whose first and last digits are the same. My hundreds digit is 6. I am divisible by 9 and 11. The sum of my digits is 18. What number am I?
Answer: The number is 3663.
Explanation:
Form: a 6 6 a.
- Sum = 2a + 12 = 18 → a = 3
- Number = 3663
Check divisibility: 3663 ÷ 9 = 407, ÷ 11 = 333.
So number is 3663.
Question 39: I am a three-digit number divisible by 5. My middle digit is 6. When added to my reverse, the sum is 726. What number am I?
Answer: The number is 660.
Explanation:
Number = 100a + 60 + c, reverse = 100c + 60 + a.
Equation: 101(a+c) + 120 = 726 → a+c=6.
Try c=0 → a=6 → number=660. Works.
Question 40: I am a two-digit number equal to 7 times the sum of my digits. The difference between my digits is 2. What number am I?
Answer: The number is 42.
Explanation:
Equation: 10x+y = 7(x+y) → 3x=6y → x=2y.
Difference: |x−y|=2.
Substitute: 2y−y=2 → y=2 → x=4 → number=42.
Question 41: I am a three-digit number divisible by 9. My hundreds digit equals the sum of my tens and ones digits. My tens digit is even, and my ones digit is prime. What number am I?
Answer: The number is 927.
Explanation:
Let digits be a b c.
- a = b + c
- c prime → {2,3,5,7}
- b even
- a+b+c divisible by 9
Try b=2, c=7 → a=9 → number=927 → sum=18 divisible by 9.
Question 42: I am a four-digit number with strictly increasing digits. My hundreds digit is 4. The sum of my digits is 16, and my number is divisible by 4. What number am I?
Answer: The number is 1456.
Explanation:
Digits increasing: a < 4 < c < d.
a+4+c+d=16.
Try a=1 → c+d=11. Pick c=5, d=6 → digits 1,4,5,6 → number=1456.
Last two digits 56 divisible by 4.
Question 43: I am a two-digit prime number. When my digits are reversed, the result is a perfect square. What number am I?
Answer: The number is 61.
Explanation:
Check reverses of primes → must be 16,25,36,49,64,81.
Reverse 61=16=4². So the number is 61.
Question 44: I am a special three-digit number that equals the sum of the factorials of my digits. What number am I?
Answer: The number is 145.
Explanation:
Check: 1!+4!+5!=1+24+120=145.
So number is 145.
