≈90×50
=4500(块)
≈90×40
=3600(块)
≈90×45
=4050(块)
①72×49≈
②71×52≈
③89×29≈
④0×11≈
⑤99×22≈
①26×34=
②※53×48=
③915÷3=
④※369÷6=
63÷3= 0×230= 4000÷5= 723÷9≈
25×20= 360÷6= 11×80= 49×62≈
改正:
①367+33=
②9﹣5.2=
③0.6×0.2=
④﹣=
⑤÷=