几道简便计算,麻烦各位了.9.99×999+9.99 7.6×7.6+7.6×3.4-7.6（1.25+12.5+0.25）×8 22.61+9×22.61

9.99×999+9.99 7.6×7.6+7.6×3.4-7.6
=9.99×999+9.99×1 =7.6×(7.6+3.4-1)
=9.99×(999+1) =7.6×10
=9.99×1000 =76
=9990
(1.25+12.5+0.25)×8
=1.25×8+12.5×8+0.25×8
=10+100+2
=112
22.61+9×22.61
=22.61×1+9×22.61
=22.61×(1+9)
=22.61×10
=226.1

9.99×999+9.99 ＝9.99×（999＋1）＝9.99×1000＝99907.6×7.6+7.6×3.4-7.6＝7.6×（7.6＋3.4－1）＝7.6×10＝76 （1.25+12.5+0.25）×8＝1.25×8＋12.5×8＋0.25×8＝10＋100＋2＝11222.61+9×22.61 ＝22.61×（1...