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 blue stickers than red stickers.
He has 90 less green stickers than
the sum of the number of blue stickers and red stickers.

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

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

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

Number of red and blue 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 red stickers
= (2 u - 80) - 1 u
= 2 u - 1 u - 80
= 1 u - 80

(b)
Number of green less than blue 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 blue 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