Question

An inventory record for the bookstore of a local college shows a receipt of 150 accounting books on May 1. Another shipment of 25 books arrived on June 15. On May 20, 100 books were sold to the students enrolled in the summer school class. On June 3, 31 books were purchased by the students enrolled off-campus. On June 17, a shipment of 150 books arrived. Find the number on hand on June 17.

Answer 1

I'd think you just need to either: use a timeline to add/subtract OR just find all the positive numbers (shipments and accountable books) and deduct the negative numbers (books sold).
May 1: 150
May 20: 150 - 100 = 50
June 3: 50 - 31 = 19
June 15: 19 + 25 = 44
June 17: 44 + 150 = 194
OR
150 + 25 + 150 = 325
-100 + (-31) = -131
325 - 131 = 194