9=1×9
108=12×9
11106=1234×9
=123456×9
=1234567×9
=12345678×9
=123456789×9
81=9×9
882=98×9
8883=987×9
88884=9876×9
=987654×9
88888887=
279×39≈ 99×73≈
54×20=10800( ) 540×200=10800( )
54×200=10800( ) 540×2=108( )
你的依据是:
- = × = 80÷10%= 42×3.14=
30%+0.45= 3.6÷0.18= 2- = 6- - =