Tam filled his wading pool with 150 liters of water. Then 138 liters splashed out. How many liters are still in the pool?

Answer 1

The wording of this problem indicates that we need to know how much is left, which indicates a subtraction problem. We began with 150L, and lost 138L. so 150 - 138 = 12, leaving 12L remaining in the pool.