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      Lesson details

      Learning outcome

      I can generalise and fluently use written multiplication strategies to calculate accurately with decimals.

      Key learning points

      1. The factorising multiples of 10 strategy can be used.
      2. With multiplication it is important to consider the magnitude of the product.
      3. Similar calculations can be used to help reason about a product.

      Keywords

      • Factorising - Factorising means to express a term as the product of its factors.

      Common misconception

      When pupils multiply decimals, they use the column method and align the decimal points.

      If the column method is used, encourage integer multiplication and use of powers of 10 to adjust the answer to the original calculation.

      Teacher tip

      Without calculating the answer, pose questions to pupils or the class to verbalise the integer multiplication with powers of 10 e.g 3.4 x 5.6 = 34 x 0.1 x 5.6 x 0.1

      Licence

      This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      A is a term which exactly divides another term.

      Correct Answer: factor, Factor

      Q2.
      Match the multiplication of these integers with their answers

      Correct Answer:$$6\times4$$ ,24

      24

      Correct Answer:$$6\times5$$ ,30

      30

      Correct Answer:$$9\times2$$ ,18

      18

      Correct Answer:$$8\times4$$ ,32

      32

      Q3.
      Complete the calculation: $$6\times$$ $$= 600$$

      Correct Answer: 100, hundred

      Q4.
      Divide 1 into 10 equal parts. What does each part represent as a decimal?

      0.00001
      0.001
      Correct answer: 0.1
      1

      Q5.
      Divide 1 into 100 equal parts. What does each part represent as a decimal?

      0.1
      Correct answer: 0.01
      0.001
      0.0001

      Q6.
      Without using a calculator, work out: $$2.4+1.28+0.3+0.13=$$

      Correct Answer: 4.11

      6 Questions

      Q1.
      A __________ is the result of two or more numbers multiplied together.

      Correct answer: product
      factor
      multiple
      prime

      Q2.
      Which of these is equivalent to 6.34?

      $$634\times0.1$$
      Correct answer: $$634\times0.01$$
      $$634\times0.001$$
      $$634\times10$$

      Q3.
      Dividing by 1000 is equivalent to __________

      $$\times0.1$$
      $$\times0.01$$
      Correct answer: $$\times0.001$$
      $$\times0.0001$$

      Q4.
      Which of these is equivalent to $$4.56\times2.3$$?

      $$456\times23\times0.1$$
      $$456\times23\times0.01$$
      Correct answer: $$456\times23\times0.001$$
      $$456\times23\times10$$

      Q5.
      Work out: $$5.8\times2.9=$$

      Correct Answer: 16.82, 16.820

      Q6.
      Using your knowledge on identifying a reasonable answer and without working out, match the calculation to the correct answer.

      Correct Answer:$$2.4\times8.4$$ ,20.16

      20.16

      Correct Answer:$$2.9\times2.5$$ ,7.25

      7.25

      Correct Answer:$$11.3\times3.1$$ ,35.03

      35.03

      Correct Answer:$$5.7\times0.2$$ ,1.14

      1.14


      To help you plan your 7 maths lesson on: Multiplying with decimals, download all teaching resources for free and adapt to suit your pupils' needs...