唉` F.2 MatHs''2條好eaSy' 真的.___.

2008-09-28 2:14 am

如題;]` 唔該d有心人救下我-v-
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1a) Jane invited some fds to her hm for a birthday party. There are12 cans of soft drink in the refrigerator. If everyine drinks approxmately 1 1/4 cans of soft drink, estimate how many persons can be served..
1b) Six packets of ice tea cost $11.9. If Robert wants to buy 70 packets, estimate the total cost..
Estimate the value of each of the following and state the estimation strategy used.
2a) 29+33+31+56+47+45+62+58+61+77
2b) 1047.2 x 6.94 4.98

回答 (1)

Train

2008-09-28 2:29 am

✔ 最佳答案

1a) Everyone drinks approx.1 1/4 cans or 1.25 cans. For estimation, we take 1.2 cans per person. Therefore, we estimate 12 cans can serve 12/1.2 or 10 persons.

1b) 6 packets costs $11.9. For estimation, we take $12.0 for 6 packets. That is $12/6 or $2 per packet. We estimate 70 packets will cost 70x$2 or $140 in total.

2a) Estimation strategy: For unit place =5,6,7,8,9, we round it up to 10. For unit place =1,2,3,4,5, we round it down to 0.

Therefore,
29+33+31+56+47+45+62+58+61+77
=30+30+30+60+50+50+60+60+60+80
=510

2b) Estimation strategy: We round the decimal numbers to integers for easy multiplication. For numbers >1000. we will round to the tenth place.

Therefore,
1047.2 x 6.94 x 4.98
=1050 x 7 x 5
=7350 x 5
=36750

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唉` F.2 MatHs''2條 好eaSy' 真的.___.

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唉` F.2 MatHs''2條好eaSy' 真的.___.