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脱式计算.(能简算的要简算)15.58÷8.2-0.729.6+9.9×998×3.6+1.4×2.80.74×4×0.25×4.

题目详情
脱式计算.(能简算的要简算)
15.58÷8.2-0.72 9.6+9.9×99 8×3.6+1.4×2.8 0.74×4×0.25×4.
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答案和解析

(1)15.58÷8.2-0.72,
=1.9-0.72,
=1.18;

(2)9.6+9.9×99,
=(9.9-0.3)+9.9×99,
=9.9+9.9×99-0.3,
=9.9×(1+99)-0.3,
=9.9×100-0.3,
=990-0.3,
=989.7;

(3)8×3.6+1.4×2.8,
=28.8+3.92,
=32.72;

(4)0.74×4×0.25×4,
=(0.74×4)×(0.25×4),
=2.96×1,
=2.96.