# Help Converting Octal to Decimal

I'm having trouble understanding the conversion of Octal Numbers to Decimals Numbers. It mostly comes down to the decimals I have most trouble with and was hoping someone could explain more in depth.

I have this number: 4.5 in octal that translates to 4.625 in decimal. Now from my understanding in Octal it goes 1-8-64-512 so: 4*1 = 4, 0.5 * 1/8 = .0625 so the answer I'm getting is 4.0625 - is there something in decimals that I'm missing?

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$5\times (1/8)$, not $0.5\times(1/8)$. –  Gerry Myerson Sep 6 '12 at 7:26

It should be $$4 \times 8^0 + 5 \times 8^{-1} = 4.625$$
and not what you are doing. You should simply multiply each digit in the number with the radix raised to the correct power, which is $0,1,2, ...$ for the digits to the left of the decimal point and $-1, -2, -3, ...$ for the digits to the right of the decimal point.