Question

初中数学题 数学强的帮帮忙

0.49*1.21*16.9
【（35.16*0.25+38.42/2)*0.5-1.63-2.37]/0.25
76*(1/23-1/53)+23*(1/53+1/76)-53*(1/23-1/76)
今天之内回复答案 过时不候 简便算法要过程

Answer 1

0.49*1.21*16.9
=[0.7*1.1*1.3]^2 *10
=[(1-0.3)(1+0.3)*1.1]^2*10
=[0.91*1.1]^2*10
=1.001^2*10
=1.01*10
=10.1

[（35.16*0.25+38.42/2)*0.5-1.63-2.37]/0.25
=[35.16/8+38.42/4-4]*4
=35.16/2+38.42-16
=17.58+38.42-16
=56-16
=40

76*(1/23-1/53)+23*(1/53+1/76)-53*(1/23-1/76)
=76/23-76/53+23/53+23/76-53/23+53/76
=(76/23-53/23)-1+23/53+53/76
=23/23-1+1
=1

Answer 2

0.49*1.21*16.9=(1-0.3)(1-0.3)(1+0.1)*(1+0.1)(1+0.3)*(1+0.3)
=(1-0.09)(1-0.09)