Reach for the Star

Place value, decimals and estimation

Pearson Edexcel GCSE Mathematics 1MA1 · Foundation and Higher · L003 · Review v0.9

Your learning journey

Use place value to scale and compare decimals, round to stated accuracy, and judge whether a calculation is reasonable.

Work without a calculator except for an invited check. Keyboard - means the same as −. Attempt before opening a scaffold or intentional practice explanation.

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Ready.

Connect & Check

Decimal place: position after the decimal point. Significant figure: a digit counted from the first non-zero digit. Estimate: an approximate calculation. Approximately equal: ≈. Placeholder zero: a zero that preserves position or stated accuracy.

Intentional practice feedback after your attempt

−5 and 12.

Keep signs and operation order separate.

Intentional practice feedback after your attempt

70; 346.

Place determines value.

Intentional practice feedback after your attempt

0.6, because 0.60 > 0.56.

Compare tenths first; digit count is not value.

Share

In pairs, predict the first step and compare your reasons before reading the worked solution: D1 Worked example: 4.063 = 4 + 0.06 + 0.003. Write 2.507 in expanded form and state the value of 5.

Present

In 4.063, the digits represent 4 ones, 0 tenths, 6 hundredths and 3 thousandths. Multiplying by ten makes each digit’s value ten times as large; the decimal point marks the boundary between ones and tenths. Pad decimals with trailing zeros to compare equal places: 0.6 = 0.60 > 0.56.

For rounding, identify the retained place and inspect the next digit. At 5 or above, increase the retained digit; otherwise keep it. Carry where needed. For significant figures, begin at the first non-zero digit. Estimate by replacing awkward numbers with convenient approximations, then compare the scale and units of the result.

Place value in 4.063
OnesTenthsHundredthsThousandths
4063

Read: four ones, zero tenths, six hundredths, three thousandths.

Optional scaffold

Label ones, tenths, hundredths and thousandths.

Intentional practice feedback after your attempt

2 + 0.5 + 0.007; 0.5.

The 5 is in the tenths place.

Optional scaffold

Track the 3 first; preserve the spacing between the digits.

Intentional practice feedback after your attempt

30.6; 0.0306.

Each digit moves into a place worth ten times as much, or one hundredth as much.

Optional scaffold

Retain hundredths; inspect thousandths.

Intentional practice feedback after your attempt

6.29.

The next digit is 6, so increase the hundredths digit.

Optional scaffold

Leading zeros locate the number; start counting at 7.

Intentional practice feedback after your attempt

0.0073.

The first two significant digits are 7 and 3; the next digit is 4.

Apply

Optional scaffold

Use a place-value chart, then cover it.

Intentional practice feedback after your attempt

5.2; 52; 0.052; 0.0052.

Compare how the same digits change value.

Intentional practice feedback after your attempt

9.98; 0.0068; 4.70.

The final zero in 4.70 communicates requested accuracy, although 4.7 is the same value.

Optional scaffold

Write the approximate expression before multiplying.

Intentional practice feedback after your attempt

20 × 5 = 100; exact 97.02. No: 970.2 is about ten times the estimate.

An estimate checks scale; it does not prove every digit correct.

After estimating A3, enter 19.8 × 4.9. Expect 97.02. Compare with 20 × 5 = 100. Read the whole display; do not round intermediate values in a multi-step calculation unless instructed.

Apply and extend

Intentional practice feedback after your attempt

Direct: 2.4. In stages: 2.45 then 2.5. The intermediate rounding changes the final result.

Keep original values until the requested rounding step.

Optional scaffold

Convert the size of the rounding unit as well as the length.

Intentional practice feedback after your attempt

2.0 m = 200 cm; 196 cm to the nearest 10 cm is also 200 cm.

The rounding units match because 0.1 m = 10 cm.

Access, Scaffold, Core and Stretch support the same goal. Stretch deepens reasoning for either qualification tier.

Recall & Review

Retrieval without notes

Six retrieval points. Enter a number, decimal, fraction such as 3/2, or mixed number such as 1 1/2. Equivalent numeric values are accepted. Unsupported notation goes to teacher review. For rounding, also communicate the requested accuracy in written work; numerical scoring cannot judge significant trailing zeros.







Not checked.

Independent exit evidence

P1–P2: five minutes, no notes, 4 marks. Your teacher reviews working and explanations. Full assessment solutions are not embedded.

Recall & Review and prepare

A useful check must test the original calculation. An inverse check undoes an operation; an estimate checks size. For 18.9 × 3.1, 20 × 3 = 60 suggests an answer near 60, not 6 or 600.

Retrieve F1 again in one week. Bring your working and one question.

Your progress summary

Completion records attempts, not mastery. Retrieval points describe the latest checked attempt. Your teacher reviews P1–P2 separately and checks retained understanding after a delay.

Restore a backup

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Optional extension activities

Stretch

Check after attempting

0.0050; estimate 400×0.05=20.

Deep challenge

Check after attempting

3.495≤x<3.505; 3.505 rounds to 3.51.

Recall & Review: feedback and extension integration

Lesson L003: Place value, decimals and estimation

Objective: Use place value to scale and compare decimals, round to stated accuracy, and judge whether a calculation is reasonable.

60-minute structure: 0-7 Connect & Check; 7-14 Share; 14-25 Present/model; 25-44 Apply route choice/practice; 44-52 independent exam-style check; 52-60 Recall & Review, WWW/EBI and next step.

What Went Well (WWW)

I selected an efficient numerical method, showed the key steps clearly and checked the sign, size or accuracy of my answer.

Even Better If (EBI)

I will make the place-value, sign or operation decision explicit and use estimation or an inverse calculation to check a fresh question.

Stretch and deep challenge

Stretch: Round 0.004976 to two significant figures and estimate 397×0.049.

Deep challenge: A number rounds to 3.50 to two decimal places. Give its interval and explain the excluded endpoint.