估算397×11≈ 207×99≈ 190×31≈49×62≈ 504×51≈ 91×68≈
脱式计算与简便运算= = = = 6﹣×﹣= 〔1﹣(﹣)〕÷= = = 5+3.6×2.5÷0.48= = = = 3.6×2÷16.9÷(3×1.1 6)×1.3= +++…+= .
=()×12=
546﹣398457+199 2.2×1015.4×99+5.432×0.125×25 .
计算:的值为多少?
脱式计算,能简便的简便. 4.2﹣1.38+5.8﹣3.620.125×0.25×32 2