What is the Decimal equivalent of 01010101?

Answer 1

That depends on what base your number is written in now.

-- If it's base-7 now, then it's equal to the decimal number 120,100 .

-- If it's base-3 now, then it's equal to the decimal number 820 .

-- If it's a binary number (base-2), then it's equal to the decimal number 85 .