(-5)×2/13×(-5) 2.(-7又3/8)×(-0.5)×(-2) 3. -12×(1/3-1/4) 4. 3又7/8×(-2又3/5)-2又7/8×(-2又3/5) 5 . 5/11×(-2/9)×(-2又1/5)×(-4又1/2)约分简便运算: 6. 1.25×(-1又1/7
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(-5)×2/13×(-5) 2.(-7又3/8)×(-0.5)×(-2) 3. -12×(1/3-1/4) 4. 3又7/8×(-2又3/5)-2又7/8×(-2又3/5) 5 . 5/11×(-2/9)×(-2又1/5)×(-4又1/2)约分简便运算: 6. 1.25×(-1又1/7
(-5)×2/13×(-5)
2.(-7又3/8)×(-0.5)×(-2)
3. -12×(1/3-1/4)
4. 3又7/8×(-2又3/5)-2又7/8×(-2又3/5)
5 . 5/11×(-2/9)×(-2又1/5)×(-4又1/2)约分简便运算:
6. 1.25×(-1又1/7)×(-3.2)×(-7/8)分数、小数互化
7. (-1/6-3/20+4/5-7/12)×(-15×4)乘法分配律
8. 4/5×(-5/13)-(-3/5)×(-5/13)-5/13×(-1又3/5)乘法分配律逆向应用
9.(-99又22/33)×(+69)拆项后用乘法分配律(提示:把-99又22/33拆成(1/23-100))
(-5)×2/13×(-5) 2.(-7又3/8)×(-0.5)×(-2) 3. -12×(1/3-1/4) 4. 3又7/8×(-2又3/5)-2又7/8×(-2又3/5) 5 . 5/11×(-2/9)×(-2又1/5)×(-4又1/2)约分简便运算: 6. 1.25×(-1又1/7
(-5)×2/13 ×(-5)
=5×2/13 ×5
=50/13
(-7又3/8)×(-0.5)×(-2)
=-(7又3/8×0.5×2)
=-7又3/8
-12×(1/3-1/4)
=-12×1/3+12×1/4
=-4+3
=-1
3又7/8×(-2又3/5)-2又7/8×(-2又3/5)
=(-2又3/5)×(3又7/8-2又7/8)
=-2又3/5
5/11×(-2/9)×(-2又1/5)×(-4又1/2)
=-(5/11×2/9×2又1/5×4又1/2)
=-(5/11×2/9×11/5×9/2)
=-(5/11×11/5)×(2/9×9/2)
=-1
1.25×(-1又1/7)×(-3.2)×(-7/8)
=5/4×(-8/7)×(-16/5)×(-7/8)
=-(5/4×8/7×16/5×7/8)
=-(5/4×16/5)×(8/7×7/8)
=-4
(-1/6-3/20+4/5-7/12)×(-15×4)
=(-1/6-3/20+4/5-7/12)×(-60)
=60×1/6+60×3/20-60×4/5+60×7/12
=10+9-48+35
=6
4/5×(-5/13)-(-3/5)×(-5/13)-5/13×(-1又3/5)
=(-5/13)×(4/5+3/5-1又3/5)
=(-5/13)×(-1/5)
=1/13
(-99又22/23)×(+69)
=(1/23 -100)×69
=69×1/23 -69×100
=3-6900
=-6897