+ = + = 2- - = -0.75=
+ = 12.5×8= 0.64÷16=
0.025×100= 0.45÷4.5= 0.25×7×4=
20×5= 20×30= 25×4= 140÷7=
550÷5= 104×2= 120×3= 120÷4=
5+ = 2- = 0.12÷0.1=