exam
Maths Puzzle
Numerical Ability
I need an equation on this problem. Thanks!
What is the sum of 1+2+3+...+20?
Read Solution (Total 1)
sum=n(n+1)/2
=20(20+1)/2
=20*21/2
=420
Ans.=420
9 years ago
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exam Other Question
Complete the ordered pairs so that each is a solution for the given equation.
3x+4y=12
(0,?), (?,3/4),(?,0), (8/3,?)
(a+b)+c=a+(b+c)
(a-b)-c=a-(b-c)