Question 1
LEVEL 4
Estimate the answer to \dfrac{18.42}{4.89}\times23.6
Select the correct answer from the list below:
A: 40
B: 55
C: 80
D: 90
CORRECT ANSWER: C: 80
WORKED SOLUTION:
Rounding each number to 1 significant figure:
18.42 rounds to 20
4.89 rounds to 5
23.46 rounds to 20
Therefore, we get:
\dfrac{18.42}{4.89}\times23.6\approx\dfrac{20}{5}\times20=4\times20=80
Question 2
LEVEL 4
Estimate the answer to \dfrac{57.33-29.88}{8.66-5.55}
Select the correct answer from the list below:
A: 20
B: 10
C: 30
D: 40
CORRECT ANSWER: B: 10
WORKED SOLUTION:
Rounding each number to 1 significant figure:
57.33 rounds to 60
29.88 rounds to 30
8.66 rounds to 9
5.55 rounds to 6
Therefore, we get:
\dfrac{57.33-29.88}{8.66-5.55}\approx\dfrac{60-30}{9-6}=\dfrac{30}{3}=10
Question 3
LEVEL 4
Jacinda wants to put 23,500ml of petrol in her car. The cost per litre is 119p. Find an estimate for how much this will cost Jacinda, give your answer in \pounds.
Select the correct answer from the list below:
A: \pounds20.00
B: \pounds23.50
C: \pounds47.00
D: \pounds60.00
CORRECT ANSWER: A: \pounds20.00
WORKED SOLUTION:
Because the answer needs to be in pounds, we should turn the cost of the petrol into pounds first.
119p =\pounds1.19
The price of petrol is also given in litres, so we need to convert this as well.
23500ml =23.5 L
Now we can start estimating.
1.19 rounds to 1
23.5 rounds to 20
Now, all we need to do is multiply these.
20\times\pounds1.00=\pounds20.00
Question 4
LEVEL 4
James wants to buy 5 pens and 3 pencils. The pens cost \pounds1.89 each and the pencils cost 45p. Find an estimate for how much this will cost James in \pounds.
Select the correct answer from the list below:
A: \pounds13.00
B: \pounds11.50
C: \pounds2.50
D: \pounds20.00
CORRECT ANSWER: B: \pounds11.50
WORKED SOLUTION:
Because the answer needs to be in pounds, we should turn the cost of the pencils into pounds first.
45p =\pounds0.45
Now we can start estimating.
1.89 rounds to 2
0.45 rounds to 0.5
And now we need to multiply these amounts by how many of each he wanted.
\textrm{(Pens) }\pounds2\times5=\pounds10
\textrm{(Pencils) }\pounds0.50\times3=\pounds1.50
And now all we need to do is add them together.
\pounds10+\pounds1.50=\pounds11.50
Question 5
LEVEL 4
Kyana is going to the cinema and needs to buy 2 adult and 2 child tickets. An adult ticket costs \pounds7.85 and a child ticket costs \pounds3.45. If Kyana also buy a large popcorn for \pounds4.55 and 4 small soft drinks for \pounds1.75 each, find an estimate for this trip to the cinema. Give your answer in \pounds.
Select the correct answer from the list below:
A: \pounds30.00
B: \pounds33.00
C: \pounds25.00
D: \pounds35.00
CORRECT ANSWER: D: \pounds35.00
WORKED SOLUTION:
7.85 rounds to 8
3.45 rounds to 3
4.55 rounds to 5
1.75 rounds to 2
And now we need to multiply these amounts by how many of each he wanted.
\textrm{(Adult tickets) }\pounds8\times2=\pounds16.00
\textrm{(Child tickets) }\pounds3\times2=\pounds6.00
\textrm{(Large popcorn) }\pounds5\times1=\pounds5.00
\textrm{(Soft drinks) }\pounds2\times4=\pounds8.00
And now all we need to do is add them together.
\pounds16.00+\pounds6.00+\pounds5.00+\pounds8.00=\pounds35.00