Software Programs

Chapter1:Numbers

1.Is 123456789 divisible by 3 or not

Solution:
Add all the digits in the given number and divide by 3

(1+2+3+4+5+6+7+8+9)/3=45/3=15

Ans:Yes

2.Is 123456  divisible by 4 or not

Solution:
Divide the number formed by the last 2 digits

56/4=14

Ans:Yes

3.Find the sum of 8+(8)^2+(8)^3+(8)^4+———-(8)^10

Solution:
The numbers are in G.P.
Formula : a(r^n-1)/r-1
a=8 , r=8, n=10

==> 8*(8^10-1)/8-1
==> 1227133512

4.Find the sum of 8+16+24+———–+80

Solution:

The numbers are in Arithmetic Progression.
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