Grade 9 · Math · Unit 6 of 15
Expressions
Build, compare and match
What your child practises
Writing an expression for a pattern or a sentence, deciding which expressions are equivalent, expanding brackets, and collecting like terms.
Ontario Curriculum expectation: C1.2, C1.3, C1.4 · creating algebraic expressions and finding equivalent ones
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Which expression is equivalent to 5(x + 7)?
- x + 35
- 5x + 7
- 5x + 35
- 5x + 12
Show answer
5x + 35
Hint: Multiply both terms inside the brackets by 5: 5 × x = 5x and 5 × 7 = 35.
Question 2
If n = 6, what is the value of 2n − 9?
answer box
Show answer
3
Hint: Replace n with 6: 2 × 6 − 9 = 3.
Question 3
Ana has 9 fewer than 5 times the number of cards Leo has. If Leo has n cards, which expression gives the number Ana has?
- 5(n − 9)
- 9n − 5
- 9 − 5n
- 5n − 9
Show answer
5n − 9
Hint: "5 times" Leo's number is 5n. "9 fewer" is taken away after that: 5n − 9.
Question 4
Which expression is NOT equivalent to 4x + 12?
- 12 + 4x
- x + 3x + 12
- 4(x + 12)
- 4(x + 3)
Show answer
4(x + 12)
Hint: Expand each one. 4(x + 3) = 4x + 12, but 4(x + 12) = 4x + 48.
Question 5
Figure n in a pattern uses 3n + 1 tiles. How many tiles does figure 20 use?
answer box
Show answer
61
Hint: Replace n with 20: 3 × 20 + 1 = 61.
Question 6
Which expression gives the number of tiles in figure n?
Figure n Tiles 1 4 2 7 3 10 4 13 - 4n
- 3n + 1
- n + 3
- 3n − 1
Show answer
3n + 1
Hint: The tiles grow by 3 each figure, so the n-term is 3n. Figure 1 has 4 tiles, so add 1.