Page 34 - Whole Numbers (Addition and Subtraction)

5. Give approximate answers for the questions below, by first
rounding off the numbers to the nearest 1 000.

(a) Selina uses 3 524 litres of water from the tank to water her
small field of maize. If there is then 4 852 litres water left,
how much water was in the tank?

(b) A store sold 8 563 packets of chips during a month. Of
these, 2 047 were sold during the last week. How many
packets were sold during the first three weeks of the month?
(c) Willem has to lay 8 675 bricks. So far he has laid 2 357
bricks. How many bricks must he still lay?

(d) Lerato walked 5 683 m. In the same period of time,
Sipho walked 7 349 m. How much further than Lerato
did Sipho walk?

6. Give better approximate answers to the above questions, by
rounding off the numbers to the nearest 100.

7. Give even better approximate answers to the above questions, by
rounding off the numbers to the nearest 10.

8. Calculate the accurate answers to the above questions.

9. Find out by how much your estimates these differences are
in question 5 differed from your called the estimation
accurate answers. Report your errors errors.
in a table like the one below.

Also find the estimation errors for your estimates in question
6 and in question 7, and report them in your table.

Question (a) (b) (c) (d)

5. Error when rounding to the nearest 1 000
6. Error when rounding to the nearest 100

7. Error when rounding to the nearest 10

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