base 10 - base 8

[solomon_13000]

Evaluate:

726 base 10 - 354 base 8

The solution is 490 but I am getting 752

how do I solve this problem.

 

[galactus]

To change from base 8 to base 10:

Write the number vertically, upside down and multiply by consecutive powers of 8

\(\displaystyle \L\\4\cdot{8^{0}}=4\)
\(\displaystyle \L\\5\cdot{8^{1}}=40\)
\(\displaystyle \L\\3\cdot{8^{2}}=192\)

Add 192+40+4=236

726-236=490

 

[soroban]

Hello, solomon_13000!

Do you know how to change from one base to another?

Evaluate: \(\displaystyle \:726_{10}\,-\,354_8\)

\(\displaystyle 354_8\) means: \(\displaystyle \:3\cdot8^2\,+\,5\cdot8\,+\,4\:=\:236\)

Therefore: \(\displaystyle \:726\,-\,236\:=\:490\)