Question

Julie made rows of counters with a box of 100 counters.Each row she made had one more counter than the row before it.The first row had 1 counter and the last row had 6. (a) How many counters did Julie use?(b) How many were left in the box?

Answer 1

Part A:

Basically, you add 1+2+3+4+5+6. (The first row had 1 counter and the last row had 6). You end up with 21 counters are used.

Part B:

Subtract 21 from 100. You will get 79.