Oliver had some erasers at first. After he bought another 81 erasers, he had four times as many erasers as before. How many erasers did Oliver have at first?
| |
Erasers |
| Before |
1 u |
| Change |
+ 81 |
| After |
1 u + 81 = 4 u |
Number of erasers after he bought = 1 u + 81
Number of erasers that is four times as many erasers as before = 4 x 1 u = 4 u
4 u = 1 u + 81
4 u - 1 u = 81
3 u = 81
1 u = 81 ÷ 3 = 27
Number of stickers that Kim had at first
= 1 u
= 27
Answer(s): 27
