口算.7.5+9.2= 9﹣2.7= 16﹣0.9= 2.6×0.3= 4.5÷0.9=8.5×10= 5.2÷0.2= 1.2×6= 7.9÷0.1= 7.6×4=4.5÷3= 0.65÷0.1= (1.5+0.25)×4= 3×0.2×0.5= 12﹣6.5﹣3.5=
×15+÷.
简便计算. ①7.7×7+7.7×2+7.7 ②87.3×45+10.7×45+2×45 ③(2.5+2.5+2.5+2.5)×2.5×8.
43.87×2.65﹣26.5×5.613=( 265 )
用简便方法计算. 15.3+0.86+0.14+4.7147×8+8×53 6900÷25÷425.3﹣8.1﹣10.9.
用简便方法计算. 3.4×0.46+3.4×0.54[18.95﹣﹙8.43+3.87﹚]×2.