Barbara used ³₄ of her brown stickers and ³₇ of her green stickers to decorate her diary. In the end, she had an equal number of brown stickers and green stickers left. Given that Barbara had a total of 161 brown and green stickers at first, how many green stickers did she use to decorate the diary?

	Brown stickers	Green stickers
Before	4x4 = 16 u	7x1 = 7 u
Change	- 3x4 = - 12 u	- 3x1 = - 3 u
After	1x4 = 4 u	4x1 = 4 u

The number of brown stickers and green stickers in the end is the same.  Make the number of brown stickers and green stickers in the end the same.  LCM of 1 and 4 is 4.

Total number of stickers that Barbara used to decorate the diary
= 16 u + 7 u
= 23 u

23 u = 161

1 u = 161 ÷ 23 = 7

Number of green stickers that Barbara used to decorate the diary
= 3 u
= 3 x 7
= 21

Answer(s): 21