Apply place-value knowledge to known additive and multiplicative number facts (scaling facts by 1 tenth or 1 hundredth) (1)

Description

Pupils must be able to combine known additive and multiplicative facts with unitising in tenths and hundredths, including:

• scaling known additive facts within 10, for example, 0.09 – 0.06 = 0.03
• scaling known additive facts that bridge 10, for example, 0.8 + 0.6 = 1.4
• scaling known multiplication tables facts, for example 0.03 × 4 = 0.12
• scaling division facts derived from multiplication tables, for example, 0.12 ÷ 4 = 0.03
• scaling calculation of complements to 100, for example 0.62 6 + 0.38 = 1

For calculations such as  0.8 0.6 1.4+ = , pupils can begin by using tens frames and countersas they did for calculation across 10 (2AS–1), calculation across 100 (3NF–3 ) and calculation across 1,000 (4NF–3), but now using 0.1-value counters (or 0.01 value counters for calculations such as 0.08 + 0.06 = 0.14).

Language focus: “8 plus 6 is equal to 14, so 8 tenths plus 6 tenths is equal to 14 tenths.” “14 tenths is equal to 1 one and 4 tenths.”

Pupils can initially use 0.1- or 0.01-value counters to understand how a known multiplicative fact, such as  3 × 5 = 15, relates to scaled calculations, such as  3 × 0.5 = 1.5 or  3 × 0.05 = 0.15. Pupils should be able reason in terms of unitising in tenths or hundreds, or in terms of scaling a factor by one-tenth or one-hundredth.

It is important for pupils to understand all of the calculations in this criterion in terms of working with units of 0.1 or 0.01, or scaling by one-tenth or one-hundredth for multiplicative calculations.  You can find out more about fluency and recording for these calculations here in the calculation and fluency section: Number, place value and number facts: 5NPV–2 and 5NF–2.