In this quiz the answers change every time you play! Given a random number, qive the cummulative of that number from 1
eg. given '4' the answer would be '10'...... ie 1 + 2 + 3 + 4 = 10
If stuck move yellow box manually:
Answer must correspond to highlighted box!
Hint: (n*(n+1))/2 ......... or .......... n*1/2n + 1/2n