A:2m/s
B:1.3m/s
C:0.67m/s
D:2.3m/s
640÷2=____ 50×10=____ 16×5=____ 480÷8=____
23×40=____ 45×30=____ 505÷5=____ 200×70=____
150000____15万
255300____255900
360÷9____120÷4.