简便运算及答案.ppt

* 一、用简便方法计算下面各题： 48.7+5.6+11.3 43.21+98.76+56.79+1.24 5.48+3.99 6.3+15.4+0.09+3.7+14.6 56.8+22.8 34.65－0.99－0.97 34.5－2.98 45.7－10.4 57.3－27.8 =48.7+11.3+5.6 =60+5.6 =65.6 =(43.21+56.79)+(98.76+1.24) =100+100 =200 =5.48+(4－0.01) =5.48+4－0.01 =9.47 =(6.3+3.7)+(14.6+15.4)+0.09 =40+0.09 =40.09 =56.8+23－0.2 =79.8－0.2 =79.6 =34.65－1－1+(0.01+0.03) =32.65+0.04 =32.69 =34.5－3+0.02 =31.5+0.02 =31.52 =45.7－10－0.4 =35.7－0.4 =35.3 =57.3－28+0.2 =29.3+0.2 =29.5 67.68－7.3－2.7 3.65－1.28－0.37－1.77 19.826－1.173－5.248－3.405 130.8－35.9+5.9 23.97+0.9+6.8 23.9+6.78－3.9 31.61－21.27－1.61 =67.68－(7.3+2.7) =67.68－10 =57.68 =3.65－(1.28+0.37) －1.77 =3.65－1.65 －1.77 =0.23 =19.826－(1.173+5.248+3.405 ) =19.826－9.826 =10 =130. 8－(35.9－5.9) =130.8－30 =100.8 =23.97+1+ 7－0.3 =31.97－0.3 =31.67 =23.9－3.9+6.78 =20+6.78 =26.78 =31.61－1.61 －21.27 =30－21.27 =8.73 27.64－(5.79+1.64) 23.12－(10.12－3.67) 20.65－(17.1－1.35) 32.75+(15.25－10.68) 30.16－23.28+15.28 0.25×4.78×4 0.98×2.5 =27.64－1.64 －5.79 =26－5.79 =20.21 =23.12－10.12+3.67 =13+3.67 =16.67 =20.65+1.35－17.1 =22－17.1 =4.9 =32.75+15.25－10.68 =48－10.68 =37.32 =30. 16－(23.28－15.28) =30.16－8 =22.16 =0.25×4×4.78 =1×4.78 =4.78 = (1－0.02) ×2.5 =1×2.5－0.02×2.5 =2.5－0.05 =2.45 4.52×0.45+5.48×0.45 42×3.9 1.4×99+1.4 0.25×7×3.6 1.25×13×1.6 10.2×0.41　 2.5×12.5×32 42×67+4.2×330 8.37×16÷8 =0.25×7×(4×0.9） =0.25×4×7×0.9 =1×7×0.9 =6.3 =1.25×13×(8×0.2） =1.25×8×13×0.2 =10×13×0.2 =26 = (10+0.2）×0.41 =10×0.41+0.2×0.41 =4.1+0.082 =4.182 =(4.52+5.48）×0.45 =10×0.45 =4.5 = 42×(4－0.1） =42×4－42×0.1 =168－4.2 =163.8 =1.4×(99+1） =1.4×100 =140 =2.5×12.5×(8×4） =(2.5×4)×(12.5×8) =10×100 =1000 =42×67+42×33 =42×(67+33） =42×100 =4200 =8.37×(16÷8） =8.37×2 =16.74 28.7÷0.35 310÷2.5÷4 11.2÷ 9.6×2.4 560÷(140÷8) 5.6×7÷4 91÷0.125 2.38×4.1+5.8×2.38+0.238 28.7×1.6÷28.7 =28.7÷(0.7×0.5） =28.7÷0.7÷0.5 =41÷0.5 =82 =310÷(2.5×4） =310÷10 =31 =1