120÷30 = 640÷80 = 360÷90 = 720÷80 =
320÷80 = 180÷30 = 100÷20 = 220÷20 =
60÷20=
4800÷80=
100÷25=
420÷70=
50×20=
300×60=
140×40=
200×16=
600×38=
397×21≈
94÷30≈
398÷8≈
510÷30= 1÷2.5=
= 1.2-0.03= 3× - ×3=
5+0.5÷0.5-5=
48×（ ）=
