5
A baker estimates that she has baked 100 loaves, to 1 significant figure. She sells two loaves and now has 90 loaves, to 1 significant figure. How many loaves did she start with? Work out all possible answers.
6
There are 500 cars in a car park, to 1 significant figure. What is the least possible number of cars that could enter the car park so that there are 700 cars in the car park, to 1 significant figure?
7
Five minutes before closing time, a supermarket manager estimates that there are still 200 people shopping, to 1 significant figure. No more shoppers can enter the supermarket. On average, a checkout serves four customers in five minutes. How many checkouts should be open so that all the customers can be served by closing time?
Homework 1D 1
2
3
Write down the answers, without using a calculator. a 50 × 600
b 0.6 × 40
c 0.02 × 400
d (30)2
e 0.5 × 250
f 0.6 × 0.7
g 30 × 40 × 50
h 200 × 0.7 × 40
Write down the answers, without using a calculator. a 4000 ÷ 20
b 8000 ÷ 200
c 400 ÷ 0.5
d 2000 ÷ 0.05
e 1800 ÷ 0.12
f 600 ÷ 0.3
g 200 × 30 ÷ 40
h 300 × 70 ÷ 0.4
You are given that 18 × 21 = 378. Use this information to write down the value of these calculations. a 180 × 210
4
5
b 3780 ÷ 21
Match each calculation with its answer and then write out the calculations in order, starting with the smallest answer. 6000 × 300
500 × 7000
10 000 × 900
20 × 80 000
3 500 000
1 800 000
1 600 000
9 000 000
The Moon is approximately 400 000 km from Earth. If a spaceship takes 8 days to travel to the Moon and return to Earth, how far does it travel each day?
Homework 1E 1
2
8
Work out approximate answers to each of these. a 4324 × 6.71
b 6170 × 7.311
c 72.35 × 3.142
d 4709 × 3.81
e 63.1 × 4.18 × 8.32
f 320 × 6.95 × 0.98
g 454 ÷ 89.3
h 26.8 ÷ 2.97
i 4964 ÷ 7.23
j 316 ÷ 3.87
k 2489 ÷ 48.58
l 63.94 ÷ 8.302
By rounding each value in the calculation, find approximate answers to each of these. 561 × 99 9.1 × 56 b 491 − 210 c 691 + 320 d 59.1 × 1.8 e a 101 18 25 2.56 989
1 Number: Basic number
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02/01/15 9:40 AM