Fill in the blanks in units (Eg 3 u) or unit equations (Eg 1 u + 2).

Bryan, Adam and Charlie have some marbles.
After Bryan's number of marbles is doubled,
Adam's number of marbles is increased by 9 and
Charlie's number of marbles is reduced by 2,
the ratio of the number of stickers of Bryan to Adam to Charlie becomes 8 : 2 : 7.

Let the number of stickers that Charlie has in the end be 7 u.

1. Number of marbles that Bryan has at first = _____
2. Number of marbles that Adam has at first = _____
3. Number of marbles that Charlie has at first = _____
4. Total number of marbles that they have at first = _____

	Bryan	Adam	Charlie
Before	4 u	2 u - 9	7 u + 2
Change	x 2	+ 9	- 2
After	8 u	2 u	7 u

(a)
Change information into units.

Number of marbles that Bryan has at first
= 8 u ÷ 2
= 4 u

(b)
Number of marbles that Adam has at first = 2 u - 9

(c)
Number of marbles that Charlie has at first = 7 u + 2

(d)
Total number of marbles that they have at first
= 4 u + 2 u - 9 + 7 u + 2
= 4 u + 2 u + 7 u - 9 + 2 
= 13 u - 7

Answer(s): (a) 4 u; (b) 2 u - 9; (c) 7 u + 2; (d) 13 u - 7