Page 17 - 新思维数学活动用书9 样章

2 Expressions and formulae

Practice

6 Zara thinks of a number, n.

I am
thinking of a
number…

Write an expression, in terms of n, for the number Zara gets when she
a subtracts 10 from the number
b divides the number by 1000

c multiplies the number by 2, then adds 3
d divides the number by 4, then subtracts 5
e divides 1 by the number, then subtracts 1
f divides 10 by double the number

g adds 20 to the number, then multiplies the result by 3
h multiplies the number by 3 then square roots the result
i multiplies the number by 4, squares the result then subtracts 3
j cube roots the number, multiplies by 6, then adds 10

k divides the number by 5, cubes the result then subtracts 9.
7 Write an expression, in terms of x, for the perimeter of each shape.
Write each expression in its simplest form.
a x b
x x

x + 5 x + 5

x x
x x
c d 5x – 2
3x 5x – 4 x
x
x
4x + 2 5x – 2

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