305000003050000 120×2012×200
425÷45425÷35 560÷16(560÷4)÷(16÷4)
⑴1200000000=亿 ⑵30000000000=亿
⑶100500000000=亿 ⑷300000000=亿
①199+199×99
②7000÷125
③1000﹣288+212
④540÷[(100﹣46)÷9]