January 6, 2014 posted by littlewhitecottage

Pirate maths… (Getting to grips with tens and units and those difficult ‘teen’ numbers)

Henry is having a bit of trouble with his ‘teen’ numbers. It’s interesting that Ollie had the same trouble in that yes, both boys can count but recognising how the numbers are written and actually understanding what each digit means had/has totally passed both of them by. It’s really important that little ones have a firm grounding in place value as the whole number system we use is based around manipulating and understanding the base 10 system. Ollie could count but had a blind spot on, for example, 13, 14, 15 etc. as to hear the number thirteen, fourteen, fifteen etc. and to write them how they sound means the digits are reversed so he would write 31 for thirteen and 41 for fourteen and I can see why; twenty three is written 23 and because he heard a number first in the teen numbers he thought that that number should be written down first. Because he wrote thirteen as 31 to see a number written as 13 thoroughly confused him so when Henry struggled I was much more prepared.

Hen doesn’t mind working a bit at home and I think he actually quite enjoys it. When I said we needed to do some ‘Pirate Maths!’ his ears pricked up and his curiosity got the better of him. He sat down and I said I wanted to tell him a story…


I told him of a pirate (Pirate Henry) that was given gold blocks as payment for his work and this was great and the pirate put the gold blocks in his pocket. As he was paid more the next week, he put the new gold blocks in his pocket with the others and this he did each week. As he went about his work he found that climbing the ropes to get to the crows nest was getting more and more difficult as his pockets were quite full and one day, while climbing, his trousers started to fall down and everyone could see his pants. He was so embarrassed as all the other pirates laughed at him. He climbed down and thought about what he could do. He decided to count his blocks to see how many he had and found it really difficult as there were so many and while he was counting (he’d laid them out on the deck which is a bit daft when you’re surrounded by naughty pirates) some of the other pirates stole a few of the blocks!

Pirate Henry had 2 problems;

1. The gold blocks were too bulky and heavy so his trousers kept falling down.

2. He couldn’t count the blocks fast enough before the other pirates stole them. He needed to be able to count faster.


We have these maths equipment (Dienes equipment) which I used both as a teacher and also with Ollie my eldest son. They are great to use to help children ‘see’ the number system. The yellow cubes (gold blocks) are single units and the long green sticks are 10 units joined together to make 1 set of 10. I’d used the yellow cubes in showing Henry the pirates gold blocks and Henry filled his pockets as I gave him Pirate Henry’s money each week. Henry put them in his trousers and as he pretended to climb the ropes to get to the crows nest I gently tugged on his trousers so it felt like they were falling down. Henry thought this very funny and he emptied out his pockets to see if he could quickly count how many gold blocks he had and he found it difficult to do in a rush so we talked about how we could solve the problem using the equipment he had. Henry suggested that we could use the blocks of 10 and exchange the gold blocks for green blocks of 10 (he’d had experience of the Dienes apparatus at school which was great) so that’s what he did. He counted 10 gold blocks and exchanged them for a stick of 10. (Yes this picture shoes a lovely pirate flag made from the yellow and green blocks)


I then said could he keep the sticks of 10 on the left and the units on the right. I asked him how many sticks of 10 he had and he said ‘1’ and I asked how many units left over and he said ‘5.’


We wrote the number down like this

T    U

                                                                                                                      1     5

When I asked him ‘How many 10’s are there?’ he could clearly see 1 and when I asked him how many units he could again clearly see 5.

Hubbie did a few more examples with Henry and they wrote them down.


 Henry wanted pirate ticks so Hubbie (who is much better at drawing than me) made each tick into a little pirate flag.

The last tick has a pair of knickers (a REALLY funny word when you’re 6) hanging off it.


Hubbie concentrated on ‘How many sets of ten and how many units left over?’ so Henry read the numbers correctly from left to right.

Hubbie also wrote a number and then Henry had to make it using the apparatus and they both counted to make sure Henry had got it right. They started from the group of ten as they knew that was 10 and then counted on the units.

Henry did really well with this activity and I think it not only helped his reading of the teen numbers but it gives him a visual memory to plug into when he finds maths hard in the future. He manipulated the numbers and then could see the numbers -and also the amounts each one where – in front of him so this gives him more of a concrete understanding of the written number when he sees it. 17 he can now say ‘that’s 1 set of 10 and 7 units so that’s seventeen’ which is what he did though we started with the lower teen numbers first.

I think using maths apparatus really help with the understanding behind the written number and if you don’t have this apparatus at home you could easily make some out of Lego bricks. Make towers of 10 of the same size and colour brick and use the same size (but different colour) for the units and you have your own set of Deines apparatus.

We’ll keep going over this in different ways with Henry but already this has helped his understanding of higer numbers as he sees the number 36, for example, and says ‘Thirty six, that’s 3 tens and 6 units’ -brilliant! And by telling him a silly pirate story and pretending to pull his pants down he has a reason as to why we group the numbers into sets of 10 and, maybe, I can find another tenuous story to tell him when we get to the hundreds!

After Hubbie and Henry had finished Henry wanted a picture of the pirate in frilly pink knickers so Hubbie drew one for him.


Henry was so impressed by this and laughed a lot that he used some of the paper and wrote this…


‘He has a big bum’ -Henry has never written anything by himself before.

Maths can be fun, it doesn’t have to be all serious and you can still learn when you laugh and draw silly pictures.

I’m going to show him the same thing using money next as he loves money and is desperate to makes sense of it, I’ll take photos and blog about it when I do.


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