Page 155 - New Medley 5 Semester 1
P. 155
Divisibility by Rules Examples
4 The number formed with the 24, 140, 200, 612, 1048, etc.
tens and ones digits should
be divisible by 4.
8 Number’s last three digits 480, 1000, 2056, 14128, etc.
should be 000, or number
formed with them is divisible
by 8.
6 The number should be 36, 48, 102, 456, 1122, etc.
divisible by both 2 and 3.
11 The difference between the 473 (4 + 3 = 7, 7 – 7 = 0),
sum of digits of the number
6809 (6 + 0 = 6, 8 + 9 =
at even and odd places
17, 17 – 6 = 11),
should be 0 or a multiple
of 11. 172909 (1 + 2 + 0 = 3,
7 + 9 + 9 = 25, 25 – 3 = 22)
Example 1: Test the following numbers divisible by 2, 3, 4, 5, 6, 8, 9
and 10.
(a) 32640 (b) 127296
Solution: (a) The number 32640 ends with 0, so it is divisible by 2,
5 and 10.
Sum of digits of this number = 3 + 2 + 6 + 4 + 0 = 15,
which is divisible by 3 but not by 9. So the number
is divisible by 3 but not by 9.
The number formed with last two digits is 40, i.e., a
multiple of 4, hence the number is divisible by 4.
The number is divisible by 2 and 3, so it is divisible by 6.
The number formed with last three digits 640 is
divisible by 8, so the number is divisible by 8.
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