15.75÷0.21=
157.5÷21=
0.75×2.1=
0.58×0.990.58 6.72÷1.236.72
5.9×7.848 0.68×1006.8×10
12.5×0.80.25×40 16.6÷1.988
9×<29 49>×7 8×<50
8×>54 21<×4 33<×7
16÷20%= 4.8÷(0.4+1.2)=
-(-)= 12÷0.25÷4=