31×20≈ 73×9≈ 52×69≈
37×19≈ 19×91≈ 88×11≈
83×96=
①48×80=
②11-2.9=
③42.3+8.4=
④55×33=
⑤328÷8 =
⑥522÷4=
= = = ≈