王老师发现不少四年级的同学脱式简便计算能力都不是很好,因此今天要给同学们讲解一下脱式简便计算怎么做。
脱式计算即递等式计算,把计算过程完整写出来的运算,也就是脱离横式的计算。在计算混合运算时,通常是一步计算一个算式(逐步计算,等号不能写在原式上),要写出每一步的过程。一般来说,等号要往前,不与第一行对齐。也就是离开原式计算。(脱字念tuo)主要掌握的是记住要先算乘、除法,后算加、减法。在乘除法连续计算时中,要按从左往右的顺序依次计算。遇到括号,要首先计算括号内部。在脱式过程中要按运算顺序划出运算顺序线,还要做到“三核对”,一要核对从书上把题抄到作业本上数字、符号是否抄对。二要核对从横式抄到草稿竖式的数字、符号是否抄对。三要核对把草稿竖式上的得数,抄到横式上是否抄对,小数点是否点对地方,有无遗漏。
如何脱式计算?
主要掌握的是记住要先算乘、除法,后算加、减法。在乘除法连继计算时中,要按从左往右的顺序依次计算。遇到括号,要首先计算括号内部。在脱式过程中要按运算顺序划出运算顺序线,还要做到“三核对”,一要核对从书上把题抄到作业本上数字、符号是否抄对。二要核对从横式抄到草稿竖式的数字、符号是否抄对。三要核对把草稿竖式上的得数,抄到横式上是否抄对,小数点是否点对地方,有无遗漏。
1.45+15×6= 2.250÷5×8= 3.6×5÷2×4= 4.30×3+8= 5.400÷4+20×5= 6.10+12÷3+20= 7.(80÷20+80)÷4= 8.70+(100-10×5)= 9.360÷40= 10.40×20= 11.80-25= 12.70+45= 13.90×2= 14.16×6= 15.300×6= 16.540÷9= 17.30×20= 18.400÷4= 19.350-80= 20.160+70= 21.18-64÷8= 22.42÷6+20= 23.40-5×7= 24.80+60÷3= 25.41+18÷2= 26.75-11×5= 27.42+7-29= 28.5600÷80= 29.25×16= 30.120×25= 31.36×11= 32.1025÷25= 33.336+70= 34.25×9×4= 35.200-33×3= 36.3020-1010= 37.12×50= 38.25×8= 39.23×11= 40.125÷25= 41.4200-2200= 42.220+80= 43.20×8×5= 44.600-3×200= 45.20+20÷2= 46.35-25÷5= 47.36+8-40= 48.2800÷40= 49.98÷14 = 50.96÷24 = 51.56÷14 = 52.65÷13 = 53.75÷15 = 54.120÷24 = 55.200÷25 = 56.800÷16 = 57.840÷21 = 58.560÷14 = 59.390÷13 = 60.600÷15 = 61.72÷24 = 62.85÷17 = 63.90÷15 = 64.96÷16 = 65.78÷26 = 66.51÷17 = 67.80÷40 = 68.100÷20 = 69.100÷4 = 70.240÷40 = 71.920÷4 = 72.300÷60= 73.64÷2 = 74.64÷4 = 75.50÷5 = 76.60÷8 = 77.96÷4 = 78.90÷6 = 79.400+80 = 80.400-80 = 81.40×80 = 82.400÷80 = 83.48÷16 = 84.96÷24 = 85.160×5= 86.4×250= 87.0×518= 88.10×76= 89.36×10= 90.15×6= 91.24×3= 92.5×18= 93.26×4= 94.7×15= 95.32×30= 96.40×15= 97.60×12= 98.23×30= 99.30×50= 100.5×700= 1.45+15×6= 135 2.250÷5×8=400 3.6×5÷2×4=60 4.30×3+8=98 5.400÷4+20×5= 200 6.10+12÷3+20=34 7.(80÷20+80)÷4=21 8.70+(100-10×5)=120 9.360÷40= 9 10.40×20= 800 11.80-25= 55 12.70+45=115 13.90×2= 180 14.16×6= 96 15.300×6= 1800 16.540÷9=60 17.30×20= 600 18.400÷4= 100 19.350-80= 270 20.160+70=230 21.18-64÷8= 10 22.42÷6+20=27 23.40-5×7= 5 24.80+60÷3=100 25.41+18÷2= 50 26.75-11×5= 20 27.42+7-29= 20 28.5600÷80=70 29.25×16= 400 30.120×25= 3000 31.36×11= 396 32.1025÷25=41 33.336+70= 406 34.25×9×4= 900 35.200-33×3= 101 36.3020-1010=2010 37.12×50= 600 38.25×8= 200 39.23×11= 253 40.125÷25=5 41.4200-2200=2000 42.220+80= 300 43.20×8×5= 800 44.600-3×200=0 45.20+20÷2= 30 46.35-25÷5= 30 47.36+8-40= 4 48.2800÷40=70 49.98÷14 = 7 50.96÷24 = 4 51.56÷14 =4 52.65÷13 = 5 53.75÷15 = 5 54.120÷24 =5 55.200÷25 = 8 56.800÷16 = 50 57.840÷21 =40 58.560÷14 = 40 59.390÷13 = 30 60.600÷15 =40 61.72÷24 = 3 62.85÷17 = 5 63.90÷15 =6 64.96÷16 = 6 65.78÷26 = 4 66.51÷17 =3 67.80÷40 = 2 68.100÷20 = 5 69.100÷4 =25 70.240÷40 = 6 71.920÷4 = 230 72.300÷60=5 73.64÷2 = 32 74.64÷4 = 16 75.50÷5 =10 76.60÷8 = 7.5 77.96÷4 = 24 78.90÷6 =15 79.400+80 = 480 80.400-80 = 320 81.40×80 =3200 82.400÷80 = 5 83.48÷16 = 3 84.96÷24 =4 85.160×5= 800 86.4×250= 1000 87.0×518= 0 88.10×76= 760 89.36×10=360 90.15×6= 90 91.24×3= 72 92.5×18= 90 93.26×4= 74 94.7×15=105 95.32×30= 960 96.40×15= 600 97.60×12= 720 98.23×30= 690 99.30×50=1500 100.5×700=3500
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