A trader in a country whose currency, the Mont (M), is in base five bought 1035 oranges at M145 each. If he sold the oranges at M245 each, what was his gain?
Worked solution (try it first)
The gain on each orange is selling price minus cost price: 245−145=105.
Multiply by the number of oranges: 1035×105.
Multiplying by 105 (five) shifts every digit one place left, just as ×10 does in base ten: 10305.