1.3 整数四则混合运算
①122﹣36+64
=122﹣(36+64)
=122﹣100
=22 订正:①
②99×25
=(100﹣1)×25
=100﹣1×25
=75 订正:②
③720÷(8×3)
=720÷8×3
=90×3
=270 订正:③
我来当裁判员!(对的画“√”,错的画“×”并改正 )
(1)437﹣37×2+8
=400×2+8
="8008"
(2)1500÷15﹣15×4
=1500÷0×4
=0
.