1300÷4÷25 =1300÷(4×25) =1300÷100 =13 101×98-98 =98×(101-1) =98×100 =9800 2.5×4.6+2.5×5.4 =(4.6+5.4)×2.5 =10×2.5 =25 25×31×4 =25×4×31 =100×31 =3100 47×62+47×38 =47×(62+38) =47×100 =4700