Question

几道五年级简便计算。

Answer 1

第一道（1+0.39+0.86)*(0.39+0.86+1.98)-(1+0.39+0.86+1.98)*(0.39+0.86)
=把（1+0.39+0.86）设为A，（0.39+0.86)设为B
=A*(B+1.98)-(A+1.98)*B
=A*B+1.98*A-A*B-1.98*B
=1.98*(A*B)
=1.98*1
=1.98
第二道
2005*200620062006-2006*200520052005
=2005*2006*100010001-2006*2005*100010001
第三道
499.05*8.5
=(500-0.95)*8.5
第四道
97.7*165+6.6*55
=97.7*165+(6.6/3)*(55*3)
=97.7*165+2.2*165
=165*(97.7+2.2)
=165*99.9
=165*(100-0.1）
能力有限