Page 41 - Maths Class 06

8. Write all the even numbers between 40 and 60.

9. Write all the odd numbers less than 20.
10. A number is divis ible by 15. By what other numbers will that number be divisible?
11. A number is divisible by 5 and 8 both. By which other number will that number be always
divisible?
12. Fill in the blanks:
(a) 1 is neither a ____________ nor a ____________ number.

(b) Every number is a ____________ and ____________ of itself.
(c) A number which has only two factors is called a ____________ .
(d) A number which having more than two factors is called ____________ number.
(e) ____________ is the smallest composite number.

(f) ____________ is the smallest even number.
(g) ____________ is the smallest prime number.

Divisibility Tests

Is 261 divisible by 3? The commonly used method is to divide 261 by 3, if the remainder is zero, the
number 261 is divisible by 3.

A divisibility test is a quick way to determine without actual division whether a whole number is divisible
by another number or not.
Let’s look at the tests for divisibility with 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 with examples of each.

Divisor Divisibility Condition Examples

2 If the last digit is 0, 2, 4, 6, 8. 4098 is divisible by 2 as it ends in 8.

3 If the sum of digits is divisible by 3. 252 is divisible by 3 as the sum 2 + 5 + 2 = 9 is
divisible by 3.

4 If number formed by the last two digits is 348 is divisible by 4 as 48 is divisible by 4.
divisible by 4.

5 If the last digit is 0 or 5. 255 is divisible by 5 as it ends in 5.

6 If the number is divisible by 2 as well as 3. 2214 is divisible by 6 as it is divisible by 2 as
well as 3.

7 Subtract twice the last digit from the number 651 is divisible by 7 as 65 – (2 × 1) = 65 – 2 =
obtained by deleting last digit. If the number 63 is divisible by 7.
obtained is 0 or multiple of 7, the number is
divisible by 7.

8 If number formed by the last three digits is 7096 is divisible by 8 as 096 is divisible by 8.
divisible by 8.

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