# Year 3 – Week 2 – Subtracting using formal written methods 1 – Monday

### About formal written subtraction for Year 3 …

MyMiniMaths introduces formal written subtraction for Year 3 with the free daily fluency, home learning and iQ mastery learning packs supported by a You Tube video tutorial. Subtracting numbers is one of the first skills learners develop in maths. Finding the difference between two quantities or values is an early skill in our maths education. Formal written methods using columns provides a method for the subtraction of larger values extending beyond our mental strategies. This takes the form of subtracting or finding the difference between 2 and 3 digit values in Year 3. The formal column or vertical method helps support the understanding of place value across the columns: units or ones, tens, hundreds, thousands and beyond. Learners need to be aware that unlike addition, the order of values has an impact on the outcome of a calculation. Values of different lengths can also be subtracted, further supporting the development of the learners’ understanding of place value, ensuring digits are placed in the correct column. From here, Year 4 are introduced to 3 & 4-digit numbers in week 2, Year 5 learners subtract 4-digit values again in week 2 before progressing to Year 6 mixed subtraction and addition this time in week 1, developing their understanding of inverse calculations. The introduction of subtracting decimal values in Year 6, not only supports the subtraction of money, but an essential real-life skill in preparation for the Key Stage 3 curriculum.

The most frequently seen errors when learners are subtracting, is not identifying the need for borrowing from an adjacent column. Reinforcing the need to borrow extra value to complete a column’s subtraction becomes increasingly important as the learner progresses through Key Stage 2. The second common error is forgetting to reduce the value that has been borrowed from, such as borrowing a ten from 40 now becomes 30. As the learner develops confidence with written subtraction, introducing subtraction from a zero often poses a challenge. In this situation, the learner needs to understand the need to borrow values one column at a time and not jump columns in order to preserve the correct place value of a digit.

### Varied Application…

Varied application is the use of 2 or more learning objectives in different contexts. Skills are readily used across the maths curriculum, often without realisation, giving opportunity for learners to apply their understanding and confidence of written subtraction for Year 3 in a variety of mathematical contexts. Varied application promotes the wider curriculum and extends the coverage of skills outside of discrete lessons. Subtracting is one of the fundamental skills required across many areas of the maths curriculum and can be applied to other Year 3 learning objectives including:

1. WEEK 5 – 10 more or less than a number
2. WEEK 14 – mental subtraction
3. WEEK 15 – subtracting length
4. WEEK 20 – further written subtraction
5. WEEK 26 – subtraction facts up to 20
6. WEEK 27 – subtracting fractions
7. WEEK 28 – subtracting mass
8. WEEK 35 – more written subtraction
9. WEEK 38 – related addition and subtraction facts
10. WEEK 46 – subtracting capacity

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