777*?*13=?? ----------------? is a two digit number.?

I have understood the question as a number say ? when multiplied by 777 and 13 will yield resultant as
??????

then ? can be any two digit from 10 to 99


Because 777 x 13 = 10101 and any two digit number multiplied by this 10101 will yield the result as the two digit number repeated thrice.
for example if ? = 11,

the answer will be 10101 x 11
= 111111

similarly for ? = 22, the answer is 222222

for ? = 33, the answer is 333333

for ? = 44, the answer is 444444

for ? = 55, the answer is 555555

for ? = 66, the answer is 666666

for ? = 77, the answer is 777777

for ? = 88, the answer is 888888

for ? = 99, the answer is 999999

777 * 1/777 * 13
= 777/777 * 13
= 1 * 13
= 13 (← two-digit number)

777*13 = 10101

10101 times any 2 digit number, say de, where d and e are its digits, the answer is dedede

for example 10101*24 = 242424

10101

hmmm.....
well, to get a two digit number

777 x 13 x (N divided by 10101) and if N is two digits the answer will be a two digit number

What are those ??...? on the RHS for? If they are not there, On LHS,
? = 1/777. Simple, is it not?