About p6 math(10marks)

1) 未用的杯=7, 杯的總數=21, 未用的佔7/21=1/3

2) 61 1/2÷1 1/2
=123/2*2/3
41

3) (3 5/8+6 1/6)÷2 11/12
=(29/8+37/6)*12/35
=(87/24+148/24)*12/35
=235/24*12/35
=47/14
=3 5/14

4) 原有8.6ml,取了3.8ml,又加回1.5ml,
現在有糖水=8.6-3.8+1.5=6.3ml

10 / 0.8
= 100 / 8
= 25 / 2
= 12 1/2 (=12.5)

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有21杯,用了14杯,

餘下了
21 - 14
= 7杯

佔全部21杯的
7/21
= 1/3

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61 1/2÷1 1/2
= 123 / 2 ÷ 3 / 2
= 123 / 2 x 2 / 3
= 123 / 3
= 41

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(3 5/8+6 1/6)÷2 11/12
=(29/8 + 37/6) ÷ 35/12
= (87/24 + 148/24) x 12/35
= 235/24 x 12/35
= 47/14
= 3 5/14

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糖水原有8.6ml,取了3.8ml,又加回1.5ml,

現在有糖水
8.6 - 3.8 + 1.5
= 6.3ml (=6 3/10)