Question

Find the difference between sum of all even numbers and all odd numbers between 1 to 20 .

Answer 1

Answer:

sum of even numbers from 1-20are...

2+4+6+8+10+12+14+16+18+20=110

sum of odd numbers are..

1+3+5+7+9+11+13+15+17+19=100

the difference is =110-100=10

hope it's helpful to you..

Answer 2

From 1 to 20

Total even number = 10 = n

= sum of the first 'n' even numbers from 1 to 20

= n(n+1) = 10× 11 = 110

From 1 to 20

Total odd number = 10 = n

= sum of the first 'n' odd number from 1 to 20

= n² = 10² = 100

therefore , required difference = 110 - 100 = 10

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