Page 46 - Mathematics Coursebook

End of unit review

End of unit review

1 Here are some decimal numbers.
5.012 0.66 19.8 123.01 2.39 23.1

Write down all the numbers that have two decimal places.

2 Write down the value of the green digit in each of these numbers.
a 132.5 b 69.27 c 4.882 d 61.05

3 a Work these out. i 49 × 10 ii 2.3 ÷ 10 iii 0.034 × 1000 iv 876 ÷ 100
b Use an inverse operation to check all your answers to part a. Show your working.

4 Copy and complete these calculations by filling in the empty boxes.
a 2.5 × = 250 b 3.2 ÷ = 0.0032 c 0.17 10 = 1.7

5 Write these numbers in order of size, starting with the smallest: 5.49, 4.2, 5.3, 5.498
6 Round 4753: a to the nearest 10 b to the nearest 100 c to the nearest 1000.

7 Round 76.189: a to the nearest whole number b to one decimal place.
8 This is part of Dafydd’s homework. Question
a Explain what Dafydd has done wrong. Round 39.47 to the nearest whole number.
Explain what Dafydd has done wrong.
b Write the correct answer.
Solution
Solution
The 7 rounds the 4 up to a 5 so 39.47 = 39.5
Then the 5 rounds the 39 up to 40.
So, 39.47 = 40 (to the nearest whole number)

9 Work these out.
a 13.45 + 9.3 b 8 + 9.76 + 23.45 c 45.95 − 23.7 d 239.8 − 47.64
10 Shona goes for a run four times a week.
During one week she runs 3.6 km, 4.85 km, 10.5 km and 7.45 km.
How far did Shona run in this week?
11 Work these out.
a 2 × 0.2 b 0.9 × 4 c 8 × 3.8 d 6 × 4.17
12 Sion sees this sign in a supermarket.
What is the cost of one jar of coffee? 3 jars of coffee for $13.89

13 For each part of this question:
i work out an estimate of the answer
ii work out the correct answer
iii compare your estimate with the accurate answer to check your answer is correct.
a 36 + 68 + 212 b 322 × 19

14 Andreas is training for a swimming competition.
The table shows the number of lengths of the
swimming pool that he swims during one week.
The swimming pool has a length of 25 m. Monday Wednesday Friday
How far does Andreas swim this week? No. of lengths 62 78 56
Use estimation to check your answer.
3 Place value, ordering and rounding 45