Question

tim abc biet abc1-2889=1abc

Answer 1

abc1 - 2889 = 1abc

abc x 10 + 1 - 2889 = 1000 + abc 

abc x 10 - abc = 1000 + 2889 - 1

abc x 10 - abc = 3888

abc x 10 - abc x 1 = 3888

abc x (10 - 1) = 3888

abc x 9 = 3888

abc = 3888 : 9

abc = 432