有關maths的問題(5分)2

用戶93083

2007-08-26 6:04 am

2. (a) Try to use the following methods of estimation to round the numbers in the expression 235 x 52 correct to the nearest ten. Then find the estimated value of the expression.

(i) Round off

(ii) Round up

(iii) Round down

(b) David wants to fill 52 cups with soft drink and each cup holds 235 ml of liquid. Pick one of the methods of estimation mentioned in (a) above to find out how many 1L bottled soft drink should be bought to fill all the cups.

回答 (1)

Gabriella Montez

2007-08-26 6:45 am

✔ 最佳答案

2ai) Round off

235 x 52 ≒ 240 x 50 = 12000

ii) Round up

235 x 52 ≒ 240 x 60 = 14400

iii) Round down

235 x 52 ≒ 230 x 50 = 11500

b) 1L = 1000ml

To choose the best method, first consider the actual volume of the soft drink, which is

52 x 235 ml = 12220 ml

Then calculate the difference between the estimated values in a)

For ai) 12220 - 12000 = 220ml

aii) 14400 - 12220 = 2180ml

aiii) 12220 - 11500 = 720ml

So, the method of rounding off is the most accurate.

Hence the number of 1L bottled soft drink that should be bought:

12000 / 1000 = 12

參考: My Maths Knowledge

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