ABC × DEED = ABCABC We know that, when we write any Number in form of ABCABC then that number must be divisible by 13 , 11 and 7 or ABCABC is multiple of 1001 So, 1001 = DEED 1001 = 13 × 11 × 7 ABC × DEED = ABC ABC ⇒ ABC × 1001 = ABC ABC On comparing D = 1, E = 0