# Unit 3 learning overview

You can use this overview to inform your planning and help secure children's learning of the mathematics covered in the unit. It includes extending number sequences forwards and backwards including decimals and negative numbers, adding and subtracting two-digit numbers mentally, solving one-step and two-step word problems, and communicating.

Children rehearse counting forwards and backwards and developing number sequences involving positive and negative numbers. They start their own sequence and challenge others to continue it, describing the rule and pattern. They extend number sequences, including those involving decimals in the context of money and length, for example they count in steps of 50 p in a sequence such as £0.50, £1.00, £1.50, £2.00, or in steps of 25 cm in a sequence like 1.25 m, 1.5 m, 1.75 m. They predict numbers that will occur in the sequence and ask 'what if?' questions, such as: 'What would my sequence look like if I counted in steps of 20 p from £1.10?'

They recognise that to enter £1.10 in a calculator they press the keys 1.1. They use the constant function to check their predictions (e.g. if they press 1.1 [+] [+] 0.2 the calculator counts in steps of 0.2 every time the [=] sign is pressed). They relate this back to counting in steps of 20 p in the context of money.

Children continue to derive pairs of numbers that total 100. They extend this to find pairs of multiples of 50 that total 1000, such as $150+850$. They continue to add and subtract two-digit numbers mentally, choosing their strategy based on the numbers involved. They investigate how many different ways they can complete an equation such as $\square \square -47=\square 9$, and they find the largest and smallest possible differences.

They solve mathematical problems and puzzles, such as: 'Lisa went on holiday. In 5 days she made 80 sandcastles. Each day she made four fewer castles than the day before. How many sandcastles did she make each day?'

Children continue to refine their written methods of calculation to make them more efficient. Those who can confidently explain how an expanded method works move on to a more compact method of recording, while others continue with an expanded method. They tackle calculations with different numbers of digits: for example, they find $754+86$ and $518-46$. They begin to add two or more three-digit sums of money, first adjusting them from pounds to pence and then moving on to using decimal notation: for example, they find the total of £4.21 and £3.87. They also begin to find the difference between amounts of money, such as $\mathrm{£}7.50-\mathrm{£}2.84$. Before they begin a calculation they use rounding to estimate the answer.

Children continue to develop written methods to multiply and divide TU by U. They estimate the answer before calculating, and recognise how partitioning helps to break down the calculation into manageable parts. They give a remainder as a whole number, recognising that it represents what is left over after a division and is always smaller than the divisor. They make sensible decisions about rounding up or down after division according to the context. When faced with a problem such as: 'A box holds six cakes. How many boxes will be needed for 80 cakes?' they recognise the need to round up, while for 'I have £62. Tickets cost £8 each. How many tickets can I buy?' they recognise the need to round down.

Children solve one-step and two-step word problems involving all four operations, some of which are in the context of money, measures or time. For each problem they select relevant information and the calculation(s) they need to do. They also decide whether to calculate mentally, use jottings to keep track of the calculation, use a written method or use a calculator. They learn how to set out a solution to a word problem by recording the calculation they have done. They communicate the main points of their solutions to each other, comparing their approaches and explaining their decisions.