Page 61 - Whole Numbers (Addition and Subtraction)

8. Which of these calculations do you think will have the same
answer, if the calculations inside brackets are done first?

(a) 3 476 + (2 328 − 2 083)

(b) 3 476 − (2 328 + 2 083)
(c) (3 476 − 2 083) + 2 328

(d) (3 476 + 2 328) − 2 083

(e) 2 328 + (3 476 − 2 083)

(f) (2 328 − 2 083) + 3 476

9. Now do the calculations to check your answer for question 8.

10. Janice has to add all these numbers together:
976 1 721 881 1 648 546

1 254 447 764 1 034 623

(a) Round each number off to the nearest 1 000 and use the
rounded figures to make an estimate of the total.

(b) Round each number off to the nearest 100 and use the
rounded figures to make a better estimate of the total.

11. Janice decides not to calculate the accurate total of the
numbers in question 10 by working in her normal way. She
decides to transfer parts between numbers so that she can end
up with easy work. For example:
• Janice transfers the 4 from the 1 034 to the 976 to make
1 030 and 980.
• Janice also transfers the 20 from the 623 to the 881 to make
603 and 901.

Rewrite the numbers in question 10 in your book. Transfer
parts like Janice did until it is very easy to add up the new
numbers.

12. Now find the total of all the new numbers that you made in
question 11.

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