Question

简便计算

12.5×9.6×2.5×15 12.5×4.8+2.5×4.48 2.2×10.4－0.88 7.3×285－73×16.5－730 怎样简便计算

Answer 1

12.5×9.6×2.5×15
=12.5x8x(4x2.5)x(0.3x15)
=100x10x4.5
=4500
12.5×4.8+2.5×4.48
=12.5x8x.0.6+2.5x4x1.12
=100x0.6+10x1.12
=60+11.2
=71.2
2.2×10.4－0.88
=2.2x10+2.2x0.4-0.88
=22+0.88-0.88
=22
7.3×285－73×16.5－730
=73x28.5-73x16.5-73x10

=73x(28.5-16.5-10)
=73x2
=146

Answer 2

涉及小数的计算，一般需要比较形式，寻找特殊的式子，如2.5×4=10,1.25×8=10,1.7-0.7=1等等这一类。因此可通过以下算法进行简便运算：
12.5×9.6×2.5×15
=12.5×（8×4×0.3）×2.5×15
=（12.5×8）×（2.5×4）×0.3×15
=100×10×4.5
=4500
12.5×4.8+2.5×4.48
=12.5×8×0.6+2.5×4×1.12
=100×0.6+10×1.12
=60+11.2
=71.2
2.2×10.4－0.88
=2.2×10.4-2.2×0.4
=2.2×(10.4-0.4)
=2.2×10
=22
7.3×285－73×16.5－730
=73×28.5-73×16.5-73×10
=73×(28.5-16.5-10)
=73×2
=146

Answer 3

12.5×9.6×2.5×15
=12.5×8×2.5×4×15×0.3
=100×10×4.5
=4500

12.5×4.8+2.5×4.48
=2.5×5×4.8+2.5×4.48
=2.5×24+2.5+4.48
=2.5×28.48
=71.2

2.2×10.4－0.88
=2.2×10.4-2.2×0.4
=2.2×(10.4-0.4)
=2.2×10
=22

7.3×285－73×16.5－730
=7.3×285－7.3×165－7.3×100
=7.3×(285-165-100)
=7.3×20
=146

Answer 4

12.5×9.6×2.5×15
=（12.5×8）×(4×2.5)×(0.3×15 )
=100×10×4.5
=4500

12.5×4.8+2.5×4.48
=12.5×8×0.6+2.5×4×1.12
=60+11.2
=71.2

2.2×10.4－0.88
=2.2×（10.4－0.4）
=2.2×10
=22

7.3×285－73×16.5－730
=7.3×285－7.3×165－7.3 ×100
=7.3×（285-165-100）
=7.3×20
=146

Answer 5

12.5×9.6×2.5×15
=12.5×（8×4×0.3）×2.5×15
=（12.5×8）×（2.5×4）×0.3×15
=100×10×4.5
=4500
12.5×4.8+2.5×4.48
=12.5×8×0.6+2.5×4×1.12
=100×0.6+10×1.12
=60+11.2
=71.2
2.2×10.4－0.88
=2.2×10.4-2.2×0.4
=2.2×(10.4-0.4)
=2.2×10
=22
7.3×285－73×16.5－730
=73×28.5-73×16.5-73×10
=73×(28.5-16.5-10)
=73×2
=146