笼中共有30只鸡和兔,数一数脚正好是100,鸡和兔各有多少只?
= .
口算 55+37= 80﹣26= 1400﹣800= 2+210= 9+300= 82+0= 1﹣= += ﹣= .
口算我最棒.+= += ﹣= ﹣=+= 1+= ﹣0.2= +0.3=+= 1﹣+= ﹣﹣= ++=
= = = =0.32= = = == 2x+x=
240﹣40÷4= 125×(8+8)= ÷12=6 2000×3+60=320×11÷32= 1﹣= 24×5﹣25×4= 8×13×25=4005÷19≈