专项一：乘除法简算-2025-2026学年五年级上册数学期末专项训练（人教版）

专项一：乘除法简算 一、乘法交换律与结合律的运用。 4.56×0.4×2.5 12.5×2.7×0.8 12.5×96×0.25 2.5×32 12.5×56 25×0.36 二、乘法分配律的运用。 0.25×10.4 12.5×8.8 99×0.35 3.7×1.8-2.7×1.8 95.7×0.28+6.3×0.28-0.28×2 1.08×9+1.08 三、比较乘法结合律与分配律在简便运算时的区别。下面各题用两种方法简算。 1.12.5×88 12.5×88 2.0.25×48 0.25×48 四、变一变，能简算。 48×0.56+44×0.48 0.279×343+0.657×279 0.264×519+264×0.481 9.16×1.53-0.053×91.6 五、拓展提高。 99.99×0.8+11.11×2.8 314×0.043+3.14×7.2-31.4×0.15 六、完全独立练习。 5×1.03×0.2 32×1.25 53×10.1 0.45×99 4.2×6.51+3.49×4.2 0.125×96 25×7.3×0.4 12.5×10.8 (20-4)×0.25 45×21-50×2.1 45×1.58+5.5×15.8 9.99×2.22+3.33×3.34一、4.56×0.4×2.5 =4.56×(0.4×2.5) =4.56×1 =4.56 2.5×32 =2.5×4×8 =10×8 =80 二、0.25×10.4 =0.25×(10+0.4) =0.25×10+0.25×0.4 =2.5+0.1 =2.6 3.7×1.8-2.7×1.8 =(3.7-2.7)×1.8 =1×1.8 =1.8 参考答案 专项一：乘除法简算 12.5×2.7×0.8 12.5×96×0.25 =12.5×0.8×2.7 =12.5×8×4×3×0.25 =10×2.7 =(12.5×8)×(4×0.25)×3 =27 =100×1×3 =300 12.5×56 25×0.36 =12.5×8×7 =25×0.4×0.9 =100×7 =10×0.9 =700 =9 12.5×8.8 99×0.35 =12.5×(8+0.8) =(100-1)×0.35 =12.5×8+12.5×0.8 =35-0.35 =100+10 =34.65 =110 95.7×0.28+6.3×0.28-0.28×2 1.08×9+1.08 =(95.7+6.3-2)×0.28 =1.08×9+1.08×1 =100×0.28 =1.08×(9+1) =28 =1.08×10 =10.8 三、1.12.5×88 12.5×88 2.0.25×48 0.25×48 =12.5×8×11 =12.5×(80+8) =0.25×4×12 =0.25×(40+8) =100×11 =12.5×80+12.5×8 =1×12 =0.25×40+0.25×8 =1100 =1000+100 =12 =10+2 =1100 =12 四、48×0.56+44×0.48 0.279×343+0.657×279 =48×0.56+0.44×48 =279×0.343+0.657×279 =48×(0.56+0.44) =279×(0.343+0.657) =48×1 =279×1 =48 =279 0.264×519+264×0.481 9.16×1.53-0.053×91.6 =264×0.519+264×0.481 =9.16×1.53-0.53×9.16 =264×(0.519+0.481) =9.16×(1.53-0.53) =264×1 =9.16×1 =264 =9.16 五、99.99×0.8+11.11×2.8 314×0.043+3.14×7.2-31.4×0.15 =11.11×9×0.8+11.11×2.8 =31.4×0.43+31.4×0.72-31.4×0.15 =11.11×(9×0.8)+11.11×2.8 =31.4×(0.43+0.72-0.15) =11.11×7.2+11.11×2.8 =31.4×1 =11.11×(7.2+2.8) =31.4 =11.11×10 =111.1 六、5×1.03×0.2 32×1.25 53×10.1 =5×0.2×1.03 =4×8×1.25 =53×(10+0.1) =1.03 =4×(8×1.25) =53×10+53×0.1 =4×10 =530+5.3 =40 =535.3 0.45×99 4.2×6.51+3.49×4.2 0.125×96 =0.45×(100-1) =4.2×(6.51+3.49) =0.125×8×12 =0.45×100-0.45×1 =4.2×10 =1×12 =45-0.45 =42 =12 =44.55 25×7.3×0.4 12.5×10.8 =25×0.4×7.3 =12.5×(10+0.8) =10×7.3 =12.5×10+12.5×0.8 =73 =125+10 =135 45×21-50×2.1 45×1.58+5.5×15.8 =45×21-5×21 =4.5×15.8+5.5×15.8 =(45-5)×21 =(4.5+5.5)×15.8 =40×21 =10×15.8 =840 =158 专项二：方程 一、x=1.1x=1x=10.8x=5x=0.7x=1.125 二、1.解：设这个数是x。 9×0.8-2x=2.4 x=2.4 2.解：设这个数是x。 (x-2)×2.6=0.78 x=2.3 3.解：设这个数是x。 2x+1.2×1.5=13.4 x=5.8 4.解：设这个数是x。 5x-3x=0.96 x=0.48 三、1.解：设师傅每天生产x个零件。 8x-32×8=128 x=48 答：师傅每天生产48个零件。 (20-4)×0.25 =20×0.25-4×0.25 =5-1 =4 9.99×2.22+3.33×3.34 =3.33×3×2.22+3.33×3.34 =3.33×(3×2.22)十3.33×3.34 =3.33×6.66+3.33×3.34 =3.33×(6.66+3.34) =3.33×10 =33.3 =0.7x=4