# Explaining subtraction with ‘renaming’ for the parents of 2nd class Room 6

At the moment the children are learning subtraction with ‘renaming’.

This methodology is required for example when you are doing a sum like:

T U

4 3

-3 5

_______

The student starts ‘taking away’ the units and realises that they can’t take 5 from 3.

We are doing subtraction with ‘renaming’ in school.

We have done a lot of practical work using Dienes Blocks.

We are at the early stages of learning how to do these kind of sums.

At the moment, for homework, the majority of the class are getting

a worksheet of subtraction without renaming.

This has caused some confusion as the children attempted to ‘rename’

when it wasn’t necessary.

Identifying when a sum will need ‘renaming’ is a skill in itself

and one which we are working on!

More confusion can arise because some parents may have learned

how to do this kind of subtraction using the

‘borrow and pay back’  method.

Another factor that may confuse you is that ‘renaming’ is also referred to as ‘regrouping’!

You might find this Tips Sheet from the NCCA helpful:

NCCA’s Tipsheet for Parents: Helping your child with subtraction

or on the Maths is Fun website below where the methodology is clearly demonstrated:

A demonstration of ‘renaming’ on the Maths is Fun website

Strategies we use – Bridging the Ten

I have found that the children who know their tables are completing these sums sooner than the children who don’t.

I am encouraging the children who find tables hard to use strategies to help them.

You might hear them talk, for example about ‘bridging the ten’.

Ask a child to take 7 from 10 and they will say 3 with confidence.

This is because they are very sure of ‘what makes 10’.

However when one asks a child a sum like 17 take away 9, they are less sure of the answer.

One of the solutions is for the child to learn the ‘make up’ of 20

and be as sure of it as they are of ‘what makes’ 10.

Again, we are working on this!

The other solution is that the child learns to ‘bridge the 10’.

Take that sum 17-9 again:

The children are fairly secure in the knowledge that 7 steps will bring them back to 10

‘Nine is one less than ten. So you add 7 and 1 and the answer is eight’.

Just in case you missed it…

I am reposting the link the the post on this blog on the importance of learning tables.

Thank you for your continuing interest and support.

Look what you can do with K’nex. Nice work Senan!

## 3 thoughts on “Explaining subtraction with ‘renaming’ for the parents of 2nd class Room 6”

1. i got 672 in the maths game.wow you guys have such a talented class if i were you i would be proud of your class great website i really really really liked your art it was amazing well done

2. Teacher |

Thanks Erin. 672 is an excellent score. You must know your tables really well and be very quick. Thank you for your encouragement. It encourages 2nd Class Room 6 to do ever better.