设, , , , , , 都是整数,试说明:在中,必有奇数个偶数.
列竖式计算. 10﹣0.45= 7.45+8.1= 8.82÷3.6= 1.25×0.54=
口算 1.2÷0.2= 2.5×4= 0.25+4= 1.87×0= 3.5+0.5= 1.2÷0.4= 3.6÷4= 0÷1.25= 0.12×6= 0.64×0.03= 5.8+4.2﹣6.5= 7.8÷3= 0.125×8= 2.8÷1.4= 0.25÷0.5= 7.21÷7= 0.35÷10= 3.6÷3= 6.3÷0.9= 0.54÷6= 0.3×0.1= 1.3÷2= 0.4÷8=2 7.3÷3= 0.51÷0.3= 15÷0.01= 5÷10= 0.7×12= 0.2×0.5= 3.8×0.1= 0.2×0.2= 0.04×0.4= 12.4+7.6= 8×0.5= 0.72÷36= 9×2.5+2.5= 1.8÷3= 2.3÷2= 6.5÷5= 2.14÷2= 2.5×4= 2.7×2= 0.5×7= 4.8+3.6+5.2= 3.4÷1.7= 2.5+0.2= 4.5÷5= 5+2.8= 0.8×0.3= 13.5×2×0= 5.25÷5= 4×2.2= 0.12×0.5= 1.8×5= 6.24÷2= 2.83﹣1.43= 1.2+2.9= 3.8÷2= 1.32×3= 4.6×7=
写得数 6.3+7= 21.5+9.5= 2.5×0.4= 42.8﹣4.28= 1﹣0.01= 3.5÷0.5= 8.2÷0.01= 8.2×0.01=
用竖式计算. 138.46﹣57.58= 6.25×0.24= 14.39÷2.4≈(保留两位小数)
笔算并验算: 25.78+72.49= 54.07﹣18.38= 1.25×32= 2.55÷0.5=