NECO 2024 · Paper 1 · Q3

Evaluate $3241_{\text{five}} - 1342_{\text{five}}$ .

Worked solution (try it first)

Change to base ten: $3241_{\text{five}} = 375 + 50 + 20 + 1$
$= 446$ and $1342_{\text{five}} = 125 + 75 + 20 + 2$
$= 222$ .
Subtract: $446 - 222 = 224$ .
Change back: $224 = 1 \times 125 + 3 \times 25 + 4 \times 5 + 4$ , so the answer is $1344_{\text{five}}$ , option B.