Teacher's Resources

5. Playing with Numbers

Click the correct answer (True & False).

If a number is divisible by 2, then it must be divisible by 4.

True

False

The least value of (x + y) if the 4-digit number 4xy7 is exactly divisible by 3 is 1.

True

False

The sum of a 2-digit number and its reversing number is always a multiple of 9.

True

False

If a number exactly divides the sum of two numbers, it must exactly divide the numbers separately.

True

False

The sum, abc + bca + cab, is exactly divisible by 111.

True

False

The difference between abc and cba is always a multiple of 89.

True

False

If the digits at the ones place of a number is 0, then the number may not divisible by 10.

True

False

A 2-digit number ab can be expressed in generalized form as a + 10b.

True

False

If the product of the digits of a number is divisible by 3, then the number is divisible by 3.

True

False

Click the correct answer.

If A × C × AC = CCC, where A and C are different digits, then what are the values of A and C?

A = 3, C = 7

A = 7, C = 3

A = 4, C = 7

A = 7, C = 4

If abc is a 3-digit number, then what is the quotient when abc – cba is divided by 99?

a – c

a + b

b + c

b – c

If abc is a 3-digit number, then what is the quotient when abc + bca + cab is divided by 37?

a + b + c

111

3(a + b + c)

a – b – c

For a 2-digit number ab, what will be the quotient if ab – ba is divided by a – b?

111

If abc is a 3-digit number, then what will be the quotient when abc – cba is divided by 33?

3(a – c)

3(a + b)

3(b + c)

3(b – c)

If abc is a 3-digit number, then what is the quotient when abc + bca + cab is divided by 3(a + b + c)?

111

a – b – c

For a 3-digit number abc, what will be the quotient if abc – cba is divided by 11?

9(a – b)

9(b – c)

9(c – a)

9(a – c)

What is the quotient when 58 + 85 is divided by 13? (Solve without actual calculations.)

What is the quotient when 73 – 37 is divided by 9? (Solve without actual calculations.)

Click the correct answer.

The generalized form of 68 is .

6 × 10⁰ + 8 × 10⁰

6 × 10⁰ + 8 × 10¹

6 × 10¹ + 8 × 10⁰

The generalized form of 97 is .

9 × 10¹ + 7 × 10⁰

9 × 10⁰ + 7 × 10¹

9 × 10⁰ + 7 × 10⁰

A number is divisible by 9 if the sum of its digits is divisible by .

A number is divisible by 6 if it is divisible by both .

3 and 4

2 and 4

2 and 3

(100 × a) + (10 × b) + c =

ab + c

abc

a + bc

In the generalized form of a 2-digit number, $$ab$$, we have $$\frac{ab - ba }{a - b} =$$ .

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