Page 21 - 新思维数学活动用书7 样章

2 Expressions, formulae and equations

5 Cheng has s strawberries. Write an expression for someone who has:
a two more strawberries than Cheng
b three times as many strawberries as Cheng
c six fewer strawberries than Cheng
d half as many strawberries as Cheng.

Practice

6 Write down an expression for the answer to each of these questions.

a Ali has x paintings. He buys two more paintings.
How many paintings does he now have?
b Hamza has t free text messages on his phone each month.
So far this month he has used 15 text messages.
How many free text messages does he have left?

c Ibrahim is i years old and Tareq is t years old. What is the
total of their ages?
d Aya can store v video clips on one memory card. How many

video clips can he store on two memory cards?
7 Nesreen thinks of a number, n. Write an expression for the number Nesreen gets each time.
a She multiplies the number by 6.
b She divides the number by 5.
c She multiplies the number by 5, then adds 1.

d She multiplies the number by 7, then subtracts 2.
e She divides the number by 10, then adds 3.
f She multiplies the number by 3, then subtracts the result from 25.

8 The cost of an adult meal in a fast-food restaurant is $a. The cost of a child’s meal in the same
restaurant is $c.
Write an expression for the total cost of the meals for these groups.
a one adult and one child
b one adult and three children

c four adults and one child
d four adults and five children

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