从1,3,5,…,99中,至少选出多少个数,其中必有两个数的和是100.
脱式计算.4.27﹣1.72+0.73﹣2.28 1.25×8.37×0.87.8﹣7.8÷(1.3×1.5) 5.28+5.28×9.
脱式计算 (能简算的要简算).72.8÷5.6+1.49 58.1﹣29.7÷3 30.94﹣5.09﹣4.913.94+34.3×0.2 5.4×2.3+5.4×7.7 3.2×12.5×0.25.
计算下面各题,怎样简便怎样计算6.89+4.7+2.11+5.3 125×25﹣125×17 7.46﹣2.37﹣1.6314﹣(3.65+0.24) 6400÷25÷4 (275﹣35)÷(17+43)
〔0.5+(2﹣0.75)〕×1.6 10.73﹣4.76﹣5.2417.4×2.43﹣1.43×7.4 2.2+(4.72﹣2.8)÷0.4.
用递等式计算.1.56﹣0.45+0.55 3.9+0.56+6.1+0.44 3.2+9.6÷0.323.12+3.12×99 1.25×3.2×25 4.75×[60÷(3.24﹣3.04)].