Question

用简便方法计算下面各题 4.8×0.25 0.78×98 0.5×

用简便方法计算下面各题
4.8×0.25 0.78×98 0.5×2.33×8 1.5×105 0.3×2.5×0.4 1.2×2.5＋0.8×2.5（递等式计算）

Answer 1

4.8×0.25=（4+0.8）×0.25=4×0.25+0.8×0.25=1+0.2=1.2
0.78×98=0.78×（100-2）=0.78×100-0.78×2=78-1.56=76.44
0.5×2.33×8=（0.5×2）×4×2.33=1×4×2.33=9.32
1.5×105=1.5×（100+5）=1.5×100+1.5×5=150+7.5=157.5
0.3×2.5×0.4=（2.5×0.4 ）×0.3=1×0.3=0.3
1.2×2.5＋0.8×2.5=（1.2+0.8）×2.5=2×2.5=5

很高兴为您解答

欢迎采纳

Answer 2

4.8×0.25
=1.2×(4×0.25)
=1.2×1
=1.2
0.78×98
=0.78×(100-2)
=0.78×100-0.78×2
=78-1.56
=76.44
0.5×2.33×8
=0.5×8×2.33
=4×2.33
=9.32
1.5×105
=1.5×(100+5)
=1.5×100+1.5×5
=150+7.5
=157.5
0.3×2.5×0.4
=0.3×(2.5×0.4)
=0.3×1
=0.3
1.2×2.5＋0.8×2.5

=(1.2+0.8)×2.5
=2×2.5
=5

Answer 3

4.8×0.25 = 1.2 x 4 x 0.25 = 1.2 x 1 = 1.2

0.78×98 = 0.78 x 100 - 0.78 x 2 = 78 - 1.56 = 76.44

0.5×2.33×8 = 0.5 x 8 x 2.33 = 4 x 2.33 = 9.32

1.5×105 = 1.5 x 100 + 1.5 x 5 = 150 + 7.5 = 157.5

0.3×2.5×0.4 = 0.03 x 2.5 x 4 = 0.03 x 10 = 0.3

1.2×2.5＋0.8×2.5 = (1.2+0.8) x 2.5 = 2 x 2.5 = 5

Answer 4

4.8*0.25=4*0.25+0.8*0.25
=1+0.2=1.2
0.78*98=0.78*（100-2）=78-1.56=76.44
0.5*2.33*8=0.5*8*2.33=4*2.33=9.32

1.5*105=1.5*（100+5）=150+7.5=157.5
0.3*2.5*0.4=0.4*2.5*0.3=1*0.3=0.3
1.2*2.5+0.8*2.5=（1.2+0.8）*2.5=2*2.5=5

Answer 5

追答

求采纳