This is a level 5 number link activity from the Figure It Out series. It relates to Stage 8 of the Number Framework.
A PDF of the student activity is included.
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multiply and divide decimals
solve currency exchange rate problems
A calculator
FIO, Link, Number, Book Five, Dreaming of Millions, page 9
A classmate
Working out currency exchange rates can be tricky, so the students may need help to work through the reasoning needed in this problem. One way is to think of the problems as proportion tasks. Ask the students “What has to be done to the NZ$1.00 to get NZ$1,500?” The answer is to multiply it by 1 500. Do the same
to the A$0.81 and you get the appropriate exchange figure, namely A$1,215. Questions 1 and 2 can be tackled in the same way.
Question 4 requires a similar strategy. For example, to work out the United States figures, it would be useful to approach the proportion as follows:
Here the question becomes: What has to be done to the US$0.4457 to make it US$1,000,000? The answer is to multiply it by 2 243 661.6 (1 000 000 divided by 0.4457), which is what you then have to multiply NZ$1 by to get the equivalent exchange figure. Note that for question 4, the decimal figure obtained on an eightdigit
calculator may vary slightly from that obtained on a 10-digit calculator and rounded to one decimal place (2 243 661.7).
Current exchange rates can be found on the Internet at www.currency.co.nz
Answers to Activity
1. a. A$1,215
b. S$1,155
2. China: Y5533.8
India: Rs31027.5
Thailand: Bht28323.15
Vietnam: D9722729.85
United States: US$668.55
Greece: EUR691.5
Philippines: P32,554.2
United Kingdom: £454.65
3. Vietnam
4. a. $2,243,661.7 (to 1 d.p.)
b. $3,299,241.2 (to 1 d.p.)
5. Answers will vary.