50×=3500 361÷≈70
40× =2800 × =2400
60×50= 900÷100= 700×10= 70×60-420=
6000÷100= 90×70= 53×2+47×2= 540÷9-60=
510÷30= 1÷2.5=
= 1.2-0.03= 3× - ×3=
5+0.5÷0.5-5=
48×( )=