解:28.08÷1.8-12.8等于( 126/45 ),【即等于2.8】
∵已知需求出28.08÷1.8-12.8等于多少
∴28.08 ÷ 1.8 - 12.8
= (28×100+8)/100 ÷ (1×10+8)/10 - (12×10+8)/10
= 2808/100 ÷ 18/10 - 128/10
= 702/25 ÷ 9/5 - 64/5
= 702/25 × 5/9 - 64/5
= 702/45 - 64/5
= 702/45 - 576/45
= 126/45
= 2.8
答:28.08÷1.8-12.8等于126/45,【即等于2.8】