| Objective | Explain the reasoning behind column addition and subtraction |
| Resources
Supplementary resources: |
Lesson Plan Powerpoint Place value counters Adding and Subtracting decimals Tarsia Enlarge onto A3 before cutting up. There is a Tarsia version available if you prefer, but unable to upload it here. Decimal addition and subtraction worksheet. Maths Loops – Decimal Subtraction (instructions in comments below) |
Bluecoat Maths 
When I taught this (at BBA) I spent a full lesson on addition and wrote a few decimal additions on the board for them to practice with different lengthed numbers to emphasise the need to line up the correct columns as this was where some were struggling. I think I will give a short worksheet at the start of next lesson to practice this before moving onto subtraction and the Tarsia activity. This will probably take about 4 lessons altogether (with added resources)
Matilde Warden
I used this loop card resource from Maths Loops https://bluecoatmaths.wordpress.com/wp-admin/post.php?post=580&action=edit
The instructions for use are here: https://bluecoatmaths.files.wordpress.com/2016/09/decimal-loops-instructions.docx
I cut the cards up and bluetacked them around the room so that the students could move around in their pairs. They took their whiteboards with them. My class really enjoyed the activity. They could tell they were wrong if they couldn’t find a card with their answer, so they were self correcting.
I’m finding that the numbers that are written in the red boxes are difficult for students to see, especially in a bright classroom. Could just be the contrast on my board though.
Thanks Michelle.
It probably is the contrast on your board, but I will make sure I use better colours in the future. Perhaps if you change the numbers to white on red for now, that might be better.
Matilde