An octopus told me that his underwater cave is $245_{8}$ years old. How many years is this in base ten?
To convert a number from base eight to base ten, I need to multiply each digit by the corresponding power of eight and add them up. For example, $245_{8}$ means $2 \times 8^2 + 4 \times 8^1 + 5 \times 8^0$. So I can calculate this by doing $2 \times 64 + 4 \times 8 + 5 \times 1$. This gives me $128 + 32 + 5 = 165$. So the octopus's cave is $165$ years old in base ten. 