+ = - = - = + =
- = - = 1- = + =
2.5×40= 0.63÷0.7= 5.7+4.23= 42=
5.8×5= 1- = 1- = 63=
0.6×0.9= 5.6÷8= 0×3.52= 0.4÷0.01=
8+2÷0.2= 7×x×0.5= 5x+1.5x= 0.52=
1 2 9 11 15 19 20 26 99 100