0.9× =                        0.5- +0.5- =

4.75+ =      72÷ =        （ ）×12=            9÷ -7÷ =

0.36÷8+0.64× =                   5× ÷5× =

=      3.9-2.45=    10÷50%=    299÷102≈

20×30%=   ×1.5=     3.6÷0.01=    1÷ =

6吨+900千克=（   ）吨       3.5立方米+350立方分米=（   ）立方米

×2.8 =        0.75+ ＝       =                ÷ =         × ÷ × =

0.4²-0.2²=       24÷5%=            － × =       120× =       18 × × =

①                                       ② 

③（－）                       ④＋