2/80:Đúng ghi Đ,sai ghi S:
a]37-5x5=12 .................................................. b]13x3-2=13 ............................................
|180:6+30=60 .................................................. |180+30:6=35 .......................................
|30+60x2=150 .................................................. |30+60x2=180 ......................................
|282-100:2=91 .................................................. |282-100:2=232 ...................................
a]37-5x5=12 Đ b]13x3-2=13 S
180:6+30=60 Đ 180+30:6=35 S
30+60x2=150 Đ 30+60x2=180 S
282-100:2=91 S 282-100:2=232 Đ
A, S Đ Đ S
B, S S S Đ