简便运算
72×125 31×99+31
3200÷25÷4 273-73-27
17×27-27×7 99×58
第1个回答 2016-03-31
72x125=9x8x125=9x1000=9000
31x99+31=31x(100+1)=31x100=3100
3200÷25÷4=3200÷(25x4)=3200÷100=32
273-73-27=273-(73+27)=273-100=173
17×27-27×7=27x(17-7)=27x10=270
99x58=(100-1)x58=100x58-58=5800-58=5742
满意请采纳
第2个回答 2016-03-31
追答
第3个回答 2016-03-31
72×125
=9x(8x125)
=9x1000
=9000
31×99+31
=31x(99+1)
=31x100
=3100
3200÷25÷4
=3200÷(25x4)
=3200÷100
=32
273-73-27
=273-(73+27)
=273-100
=173
17×27-27×7
=27x(17-7)
=27x10
=270
99×58
=(100-1)x(60-2)
=100x60- 200-60 +2
=6000 -260 +2
=5740+2
=5742
=9x(8x125)
=9x1000
=9000
31×99+31
=31x(99+1)
=31x100
=3100
3200÷25÷4
=3200÷(25x4)
=3200÷100
=32
273-73-27
=273-(73+27)
=273-100
=173
17×27-27×7
=27x(17-7)
=27x10
=270
99×58
=(100-1)x(60-2)
=100x60- 200-60 +2
=6000 -260 +2
=5740+2
=5742
第4个回答 2016-03-31
第5个回答 2016-03-31
72×125
=9×8×125
=9×（8×125 ）
=9×1000
=9000
31×99+31
=31×（99+1）
=31×100
=3100
3200÷25÷4
=3200÷（25×4）
=3200÷100
=32
273-73-27
=273-（73+27）
=273-100
=173
17×27-27×7
= 27×（17-7）
=27×10
=270
99×58
=（100-1）×58
=100×58-1×58
=5800-58
=5742
=9×8×125
=9×（8×125 ）
=9×1000
=9000
31×99+31
=31×（99+1）
=31×100
=3100
3200÷25÷4
=3200÷（25×4）
=3200÷100
=32
273-73-27
=273-（73+27）
=273-100
=173
17×27-27×7
= 27×（17-7）
=27×10
=270
99×58
=（100-1）×58
=100×58-1×58
=5800-58
=5742
