Devisibility rules for 3, 6, and 9

★ Divisibility rule for 3 -

If the sum of all the digits divisible by 3 then the number is divisible by 3.

Here, we take an example for better understanding -

Example 1 - 3525

Add up the digits - 3 + 5 + 2 + 5

→ 15

As, 15 is divisible by 3. So, 3525 is a factor of 3.

★ Divisibility rule for 6 -

A number is to be divisible by 6 , if the number is also divisible by 2 and 3.

Example 2 - 132

Add up the digits = 1 + 3 + 2 = 6

As, 6 is divisible by 2 and it's also divisible by 3. Then, 132 is a factor of 6.

★ Divisibility rule for 9 -

If the sum of all the digits is divisible by 9 then the number is divisible by 9. Just like we'd in 3.

Example 3 - 1052

Add up the digits - 10 + 5 + 2 = 17

As, 17 is not divisible by 9. So, 1052 is also not divisible by 9.

13

step-by-step explanation:

169-1=168

168-3=165

165-5=160

160-7=153

153-9=144

144-11=133

133-13=120

120-15=105

105-17=88

88-19=69

69-21=48

48-23=25

25-25=0

since it took 13times to completely subtract it hence its square root is 13

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