Page 29 - 新思维数学活动用书9 样章

2 Expressions and formulae

2 Copy and complete these calculations.
Use your answers to Question 1. The first one has been done for you.

x
a x += 2 x b x + 2 x = c 2y + 3y =
3 3 3 5 5 7 7

d y + 3 y = 4 y = e m + 2 m = = f 3n + 3n = =
8 8 8 9 9 10 10
3 Work out the answers to these calculations by finding a common denominator.

3
3
a 1 += 2 +=
4 8 8 8 Tip
1
In part b, change
b 1 + 2 = + = 3
3 9 into .
9
1
c 2 −= − = =
3 6

1
d 11 −= − = =
12 6

4 Write the answers to these calculations.
Use your answers to Question 3.

b
a x + 3 x = b y + 2 y = c 2p − p = d 11b −=
4 8 3 9 3 6 12 6
Practice

5 Simplify each expression.
a x + x b 3x + x c 6 + 6 d 5x + x e 7 + 3
4 4 5 5 x x 7 7 8x 8x
f y − y g 2y − 4y h 2y − 11y i 5 − 5 j 3 − 1
3 6 3 9 3 18 8y 16y 4y 24y
6 Here are some algebraic fraction cards.

A 9x − 13x B x + x C 2x + 3x D 11x − 13x E 11x − 2x F x + x
10 20 6 3 7 14 18 36 15 5 12 6
a Simplify each expression then sort the cards into two groups.

Explain your reasons for sorting the cards.
b Which card does not fit into either of the groups?
Explain why.

28