Multiplying Decimals by Estimating

Multiplying Decimals by Estimating uses a quick estimate to decide where the decimal point goes in a product, a handy check in NSW Year 7 maths (NESA outcome MA4‑FRC‑C‑01). Rounding \(4.9 \times 6.2\) to \(5 \times 6 = 30\) tells you the exact answer must be close to 30.

You will use a known whole-number fact, such as \(57 \times 83 = 4731\), to work out related products like \(0.57 \times 83\), place the decimal point from an estimate, and spot answers that are clearly too big or too small. Paying for petrol by the litre or fabric by the metre shows why this matters. It is part of Year 7 Decimals.