1)69*0,63=69*63/100=69*63/100=4347/100=43,47
2)10,098/5,4=10098/1000/54/10=10098*10/1000*54=10098/54000=187*540/100*540=187/100=1,87
3)43,47-1,87=4347/100-187/100=4347-187/100=4160/100=208*20/5*20=208/5=41,6
4)41,6-20,54=416/10-2054/100=416*10/10*10-2054/100=4160/100-2054/100=4160-2054/100=2106/100=1053*2/50/2=1053/50=21,06
5)21,06:0.324=2106/100/324/1000=2106*1000/100*324=2106000/32400=65*32400/32400=65
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Где(/) это дробное деление.