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1 将下面的分数转化成小数,除不尽的保留两位小数。(每题1分,共10分)
$\frac{3}{4}= $ $\frac{9}{20}= $ $\frac{4}{5}= $ $\frac{3}{7}\approx$ $\frac{6}{11}\approx$
$\frac{2}{12}\approx$ $\frac{15}{12}= $ $\frac{7}{8}= $ $\frac{13}{5}= $ $\frac{9}{24}= $
$\frac{3}{4}= $ $\frac{9}{20}= $ $\frac{4}{5}= $ $\frac{3}{7}\approx$ $\frac{6}{11}\approx$
$\frac{2}{12}\approx$ $\frac{15}{12}= $ $\frac{7}{8}= $ $\frac{13}{5}= $ $\frac{9}{24}= $
答案
0.75 0.45 0.8 0.43 0.55
0.17 1.25 0.875 2.6 0.375
0.17 1.25 0.875 2.6 0.375
2 将下面的小数转化成分数。(每题1分,共10分)
$0.25= $ $1.125= $ $0.7= $ $0.32= $ $0.08= $
$2.1= $ $0.75= $ $0.375= $ $0.6= $ $0.15= $
$0.25= $ $1.125= $ $0.7= $ $0.32= $ $0.08= $
$2.1= $ $0.75= $ $0.375= $ $0.6= $ $0.15= $
答案
$\frac{1}{4}$ $\frac{9}{8}$ $\frac{7}{10}$ $\frac{8}{25}$ $\frac{2}{25}$
$\frac{21}{10}$ $\frac{3}{4}$ $\frac{3}{8}$ $\frac{3}{5}$ $\frac{3}{20}$
$\frac{21}{10}$ $\frac{3}{4}$ $\frac{3}{8}$ $\frac{3}{5}$ $\frac{3}{20}$
3 计算下列各题,能简算的要简算。(每题3分,共18分)
$7.28 - 3.2÷2.5$ $2.08×(9.6÷2.4)÷0.8$ $(1.5 + 0.25)×4$
$99×4.3$ $89.3×43 + 38×89.3 + 1.9×893$ $24.6 - 4.8×3.7$
$7.28 - 3.2÷2.5$ $2.08×(9.6÷2.4)÷0.8$ $(1.5 + 0.25)×4$
$99×4.3$ $89.3×43 + 38×89.3 + 1.9×893$ $24.6 - 4.8×3.7$
答案
6 10.4 7
425.7 8930 6.84
425.7 8930 6.84
4 解方程。(每题4分,共12分)
$2.8x - 1.6 = 46$ $2(x - 0.5) = 1.6$ $4x + 3×0.7 = 6.5$
$2.8x - 1.6 = 46$ $2(x - 0.5) = 1.6$ $4x + 3×0.7 = 6.5$
答案
解：$x = 17$ 解：$x = 1.3$ 解：$x = 1.1$
