Page 60 - 新思维数学学生用书7 样章

2 Expressions, formulae and equations

Check your progress

1 Nimrah thinks of a number, n.
Write an expression for the number Nimrah gets each time when she
a multiplies the number by 4

b subtracts 6 from the number
c adds 12 to the number
d multiplies the number by 3, then adds 5.
2 Work out the value of each expression.
a 2a + 3 when a = 8 b p − q when p = 13 and q = 7

c b _ 5 when b = 27
3
3 Loli lives with three friends. They share the gas bill equally between the four of them.

a Write a formula to work out the amount they each pay, in:
i words ii letters
b Use your formula in part a ii to work out the amount they each pay when the gas

bill is $96.
4 Simplify these expressions.
a n + n + n b 3c + 5c
c 9x − x 2 d 3xy + 5yz − 2xy + 3zy
2
5 Expand the brackets.

a 3(x + 2) b 6(3 − w) c 4(3x + 2) d 3(7 − 4v + 6w)
6 Solve each of these equations and check your answers.
a n + 3 = 8 b m – 4 = 12 c 3p = 24 d 2h + 6 = 24
7 Marcus and Zara have set some puzzles. Write an equation for each puzzle.

Solve your equations to find the values of the unknown numbers.
a b
I think of a
I think of a number. I multiply it
number and add 3. by 2 then add 4. The
The answer is 22. answer is 28.

8 Write down the inequality shown on this number line.

4 5 6 7 8 9 10

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