Fill in the blanks.
For (a) to (c), give the answers in units (Eg 1 u) or unit equations (Eg 1 u + 2).

Adam has some stickers.
He has 10 more red stickers than blue stickers.
He has 90 less green stickers than
the sum of the number of red stickers and blue stickers.

1. How many more green stickers than blue stickers are there?
2. How many less green stickers than red stickers are there?
3. How many red and green stickers are there?

(a)
Choose the smallest group to be 1 u.

Number of blue stickers = 1 u
Number of red stickers = 1 u + 10

Number of blue and red stickers
= 1 u + 1 u + 10
= 2 u + 10

Number of green stickers
= 2 u + 10 - 90
= 2 u - 80

Number of green stickers more than blue stickers
= (2 u - 80) - 1 u
= 2 u - 1 u - 80
= 1 u - 80

(b)
Number of green less than red stickers
= (1 u + 10) - (2 u - 80)
= 1 u + 10 - 2 u + 80
= 10 + 80 + 1 u - 2 u
= 90 - 1 u

(c)
Number of red and green stickers
= 1 u + 10 + 2 u - 80
= 1 u + 2 u + 10 - 80
= 3 u - 70

Answer(s): (a) 1 u - 80; (b) 90 - 1 u; (c) 3 u - 70