Anna had 99 more buttons than Zoe. After Zoe gave away
37 of her buttons, Anna had four times as many buttons as Zoe. How many buttons did Zoe have at first?
| |
Anna |
Zoe |
Comparing Anna and
Zoe at first |
99 more |
|
| Before |
16 u |
7 u |
| Change |
|
- 3 u |
| After |
16 u |
4 u |
Comparing Anna and
Zoe in the end |
4x4 =
16 u |
1x4 =
4 u |
Number of buttons that Zoe had in the end is repeated. Make the number of buttons that Zoe had in the end the same. LCM of 1 and 4 is 4.
Number of buttons that Anna had at first = 16 u
Number of buttons that Anna had more than Zoe at first
= 16 u - 7 u
= 9 u
9 u = 99
1 u = 99 ÷ 9 = 11
Number of buttons that Zoe had at first
= 7 u
= 7 x 11
= 77
Answer(s): 77
