第六单元计算专项07：整数加法运算律推广到小数“思维拓展”-2025-2026学年四年级数学下册人教版

2025-2026学年四年级数学下册人教版 第六单元计算专项07：整数加法运算律推广到小数“思维拓展” 日期： 用时： 评价： 一、分组凑整 (1)0.7 + 0.77 + 0.777 + 0.23 + 0.223 (2)1.25 + 3.75 + 2.4 + 7.6 (3)0.9 + 0.99 + 0.999 + 0.1 + 0.01 + 0.001 (4)2.5 + 1.8 + 7.5 + 8.2 (5)0.66 + 0.34 + 0.55 + 0.45 + 0.2 (6)3.14 + 5.86 + 2.3 + 7.7 (7)0.88 + 0.12 + 0.99 + 0.01 + 1.5 (8)4.6 + 5.4 + 0.78 + 0.22 + 3 (9)0.5 + 0.55 + 0.45 + 0.5 + 0.6 (10)1.1 + 2.2 + 3.3 + 6.7 + 7.8 + 8.9 二、拆分凑整 (1)8.9 + 8.99 + 8.999 + 0.3 (2)19.9 + 19.99 + 19.999 + 0.3 (3)5.98 + 5.99 + 6.01 + 6.02 (4)9.95 + 9.96 + 9.97 + 9.98 + 9.99 + 0.25 (5)7.8 + 7.9 + 8 + 8.1 + 8.2 (6)10.1 + 10.2 + 10.3 + 9.7 + 9.8 + 9.9 (7)3.99 + 4.98 + 5.97 + 0.06 (8)12.9 + 12.99 + 12.999 + 0.3 (9)6.5 + 6.6 + 6.7 + 6.8 + 6.9 + 3.5 (10)199.9 + 19.9 + 1.9 + 0.3 三、减法的性质 (1)30.5 - 7.2 - 2.8 - 0.5 (2)50 - 12.3 - 7.7 - 15.6 - 4.4 (3)18.75 - 3.4 - 6.6 - 8.75 (4)45.6 - (5.6 + 12.5) (5)25.4 - 2.7 - 7.3 - 5.4 (6)60 - 18.9 - 11.1 - 15.3 - 4.7 (7)100.1 - 50.5 - 9.5 - 0.1 (8)36.8 - (6.8 + 3.2 + 6.8) (9)15.25 - 4.75 - 5.25 - 0.25 (10)72.3 - 12.1 - 7.9 - 22.3 - 8.5 - 1.5 第 1 页 共 1 页 学科网（北京）股份有限公司 参考答案 一、分组凑整 (1)原式=(0.77+0.23)+(0.777+0.223)+0.7 =1+1+0.7 =2.7 (2)原式=(1.25+3.75)+(2.4+7.6) =5+10 =15 (3)原式=(0.9+0.1)+(0.99+0.01)+(0.999+0.001) =1+1+1 =3 (4)原式=(2.5+7.5)+(1.8+8.2) =10+10 =20 (5)原式=(0.66+0.34)+(0.55+0.45)+0.2 =1+1+0.2 =2.2 (6)原式=(3.14+5.86)+(2.3+7.7) =9+10 =19 (7)原式=(0.88+0.12)+(0.99+0.01)+1.5 =1+1+1.5 =3.5 (8)原式=(4.6+5.4)+(0.78+0.22)+3 =10+1+3 =14 (9)原式=(0.5+0.5)+(0.55+0.45)+0.6 =1+1+0.6 =2.6 (10)原式=(1.1+8.9)+(2.2+7.8)+(3.3+6.7) =10+10+10 =30 二、拆分凑整 (1)原式=(8.9+0.1)+(8.99+0.01)+(8.999+0.001)+(0.3−0.1−0.01−0.001) =9+9+9+(0.3−0.111) =27+0.189 =27.189 (2)原式=(19.9+0.1)+(19.99+0.01)+(19.999+0.001)+(0.3−0.1−0.01−0.001) =20+20+20+(0.3−0.111) =60+0.189 = 60.189 (3)原式=(5.98+6.02)+(5.99+6.01) =12+12 =24 (4)原式=(9.95+0.05)+(9.96+0.04)+(9.97+0.03)+(9.98+0.02)+(9.99+0.01)+(0.25-0.05-0.04-0.03-0.02-0.01) =10+10+10+10+10+0.1 =50.1 (5)原式=(7.8+8.2)+(7.9+8.1)+8 =16+16+8 =40 (6)原式=(10.1+9.9)+(10.2+9.8)+(10.3+9.7) =20+20+20 =60 (7)原式=(3.99+0.01)+(4.98+0.02)+(5.97+0.03) =4+5+6 =15 (8)原式=(12.9+0.1)+(12.99+0.01)+(12.999+0.001)+(0.3−0.1−0.01−0.001) =13+13+13+(0.3−0.111) =39 +0.189 =39.189 (9)原式=(6.5+3.5)+(6.6+6.9)+(6.7+6.8) =10+13.5+13.5 =37 (10)原式=199.9+19.9+1.9+0.1+0.1+0.1 =(199.9+0.1)+(19.9+0.1)+(1.9+0.1) =200+20+2 =222 三、减法的性质 (1)原式=(30.5-0.5)-(7.2+2.8) =30-10 =20 (2)原式=50-(12.3+7.7)-(15.6+4.4) =50-20-20 =10 (3)原式=(18.75-8.75)-(3.4+6.6) =10-10 =0 (4)原式=45.6-5.6-12.5 =40-12.5 =27.5 (5)原式=(25.4-5.4)-(2.7+7.3) =20-10 =10 (6)原式=60-(18.9+11.1)-(15.3+4.7) =60-30-20 =10 (7)原式=(100.1-0.1)-(50.5+9.5) =100-60 =40 (8)原式=36.8-6.8-3.2-6.8 =30-(3.2+6.8) =30-10 =20 (9)原式=(15.25-5.25)-(4.75+0.25) =10-5 =5 (10)原式=(72.3-22.3)-(12.1+7.9)-(8.5+1.5) =50-20-10 =20 $