三角形的面积等于平行四边形的面积的一半.
0.4×0.7= 3.6÷0.9= 5.8×0.5=
70.7÷7= 0.63÷0.7= 0.125×8=
0.1÷0.01= 10.01×100=
9.75-4.25×1.2=
A.21-5=16
B.9x=0
C.x÷32=2
D.3x-2x=18÷5
①6x-1=0.2
②x: =21:
③3.5x-x=30
1.2×2.5+0.8×2.5=