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Class 8 Maths — Playing with numbers

Use the divisibility tests and letter-for-digit puzzles to find missing digits.

Name: ________________________

  1. 1.What digit must replace the star so that 21*8 is divisible by 9?

  2. 2.In the sum A7 + 4A = 113, the letter A stands for one digit. What digit is A?

  3. 3.Put these numbers in order by how many of 2, 3, 5 and 9 divide into them exactly, fewest first.

    • 15
    • 4
    • 7
    • 18
    • 90

  4. 4.A two-digit number is written as 10a + b, where a is its tens digit and b is its units digit. If a is 4 and b is 7, what is the number?

  5. 5.Take any two-digit number and subtract the number made by reversing its digits. The difference is always divisible by which number?

  6. 6.5*7 is divisible by 3. What is the largest digit that can replace the star?

  7. 7.Take any two-digit number and add the number made by reversing its digits. The total is always divisible by which number?

  8. 8.Match each divisibility test to the number it tests for.

    • The last digit is 0 or 5
    • The digits add to a multiple of 3
    • The last two digits make a multiple of 4
    • The digits add to a multiple of 9
    • The last digit is even
    • 3
    • 5
    • 4
    • 9
    • 2

Answer key — Class 8 Maths — Playing with numbers

  1. 1. 7
  2. 2. 6
  3. 3. 1. 7 2. 4 3. 15 4. 18 5. 90
  4. 4. 47
  5. 5. 9
  6. 6. 9
  7. 7. 11
  8. 8. The last digit is 0 or 5 → 5; The digits add to a multiple of 3 → 3; The last two digits make a multiple of 4 → 4; The digits add to a multiple of 9 → 9; The last digit is even → 2