16 students share some stickers.
Each boy gets 2 stickers.
Each girl gets 3 stickers.
In total, the boys get 12 more stickers than the girls.

1. How many girls are there?
2. How many boys are there?
3. How many stickers do the girls get?
4. How many stickers do the children get?

Number of boys	Total stickers that the boys get	Number of girls	Total stickers that the girls get	More stickers for the boys than the girls
16	16 x 2 =  32	0	0 x 3 = 0	32 - 0 = 32
15	15 x 2 = 30	1	1 x 3 = 3	30 - 3 = 27
12	12 x 2 = 24	4	4 x 3 = 12	24 - 12 = 12

(a)
Number of more stickers for the boys than the girls if all the students are boys,
= 16 x 2
= 32

Number of more stickers for the boys than the girls if one boy is replaced by a girl 
= 15 x 2 - 1 x 3
= 30 - 3
= 27

Big difference in the decrease in the number of stickers when a boy is replaced by a girl
= 32 - 12
= 20

Small difference in the decrease in the number of stickers when a boy is replaced by a girl
= 2 + 3
= 5

Number of girls
= 20 ÷ 5
= 4

(b)
Number of boys
= 16 - 4
= 12

(c)
Number of stickers that the girls get
= 4 x 3
= 12

(d)
Number of stickers that the boys get
= 12 x 2
= 24

Total number of stickers
= 12 + 24
= 36

Answer(s): (a) 4; (b) 12; (c) 12; (d) 36