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5.一块长方形菜地,长是56 m,宽是32.4 m。这块菜地的周长和面积各是多少?
(结果保留整数)
(结果保留整数)
答案
周长：
$(56 + 32.4) × 2$
$= 88.4 × 2$
$= 176.8$
$≈ 177(\mathrm{m})$
面积：
$56 × 32.4 = 1814.4 ≈ 1814(\mathrm{m}^2)$
答：这块菜地的周长约是177m，面积约是1814m²。
$(56 + 32.4) × 2$
$= 88.4 × 2$
$= 176.8$
$≈ 177(\mathrm{m})$
面积：
$56 × 32.4 = 1814.4 ≈ 1814(\mathrm{m}^2)$
答：这块菜地的周长约是177m，面积约是1814m²。
6.计算下面各题。
12.3×2.6+8.02
22−1.6×0.7
4.56+5.44×6.5
22.4−1.24×0.8
8.05×3.6−3.6
0.72×0.5×0.4
0.76×99
0.5×4.65×6
0.7×2.5×0.4
12.3×2.6+8.02
22−1.6×0.7
4.56+5.44×6.5
22.4−1.24×0.8
8.05×3.6−3.6
0.72×0.5×0.4
0.76×99
0.5×4.65×6
0.7×2.5×0.4
答案
12.3×2.6+8.02
=31.98+8.02
=40
22-1.6×0.7
=22-1.12
=20.88
4.56+5.44×6.5
=4.56+35.36
=39.92
22.4-1.24×0.8
=22.4-0.992
=21.408
8.05×3.6-3.6
=(8.05-1)×3.6
=7.05×3.6
=25.38
0.72×0.5×0.4
=0.72×(0.5×0.4)
=0.72×0.2
=0.144
0.76×99
=0.76×(100-1)
=0.76×100-0.76×1
=76-0.76
=75.24
0.5×4.65×6
=0.5×6×4.65
=3×4.65
=13.95
0.7×2.5×0.4
=0.7×(2.5×0.4)
=0.7×1
=0.7
=31.98+8.02
=40
22-1.6×0.7
=22-1.12
=20.88
4.56+5.44×6.5
=4.56+35.36
=39.92
22.4-1.24×0.8
=22.4-0.992
=21.408
8.05×3.6-3.6
=(8.05-1)×3.6
=7.05×3.6
=25.38
0.72×0.5×0.4
=0.72×(0.5×0.4)
=0.72×0.2
=0.144
0.76×99
=0.76×(100-1)
=0.76×100-0.76×1
=76-0.76
=75.24
0.5×4.65×6
=0.5×6×4.65
=3×4.65
=13.95
0.7×2.5×0.4
=0.7×(2.5×0.4)
=0.7×1
=0.7
