Addition & Subtraction St.Mary’s Catholic Primary School

Aims To develop your knowledge and understanding of how numeracy is taught at St.Mary’s. To increase your ability to help your children with their homework.

Calculations All calculations are based on secure mental and oral work. A structured approach to calculations, starting in Early Years with mental counting and counting of objects. This leads to early stages of mental calculation and learning number facts, recording in a number statement. We then move on to working with larger numbers and informal jottings. In Year 3, children begin to use non-standard expanded written methods, then in Year 4, these written methods become standard. Calculations have moved from being vertical ways explained by ‘because she told me to’, to horizontal breakdowns of the numbers involved. The emphasis is on understanding methods.

Addition Children in Year 1 may solve addition problems using a simple number line:

Addition Once children have gained experience and understanding in counting objects and know all addition and subtraction facts to 20, they begin to work with larger numbers and informal jottings in Yr2 and Yr3. The children will become familiar with breaking down their numbers into tens and units, for example; may be done as = 50, then = 7, then = 57.

Addition The children may also explore addition through using the number line further = 84

Addition This leads on to non-standard expanded written methods, in Yr3. Again here we are building on the concept of breaking down numbers into their place value, then recombining. For example; = = = = 17 = 427

Addition Children then may move onto column addition and using money and decimals This strategy reinforces partitioning and place value.

Addition Children may then move onto more formal column addition strategies

Subtraction The children’s early experiences of subtraction will focus on lots of practical ‘taking away’ and ‘finding the difference’. The children will make informal jottings, including counting up from the smallest number.

Subtraction Children will become able to use the number line strategy = 47

Subtraction This can then lead to a quicker way, called complementary addition; 237 – 198 = = = 237, altogether we’ve added 39, there is a difference of 39.

Subtraction Children may then move onto more formal methods

Subtraction The children may then explore the method of Decomposition, which is breaking down the numbers into their place value. They may also move onto column subtraction for using decimals.

Ways Ahead! If you would like further support with helping your child with their addition and subtraction skills, please ask your child’s teacher. They will be happy to help. Please remember that numeracy activities should be fun and built upon secure mental maths skills.