11 Plus Exams Forum

My ds who has just finished year 4 keeps making errors on place order questions such as: how many hundredths are there in 34.8
Or what is 4 hundreds plus 8 tenths plus 35 hundredths equal?
Not sure if they've covered this at school in year 4?
Should I leave these questions for a few months and hope the school will cover it in the autumn term of year 5 or should I keep repeating these questions over the summer? I don't want him to lose his confidence in maths as he's generally capable.
Any suggestions
Thanks
Bob

This is a commpn confusion as hundreds and hundredths sound similar.

Get him to label columns H T U. t h and look for (google) 'place value charts with decimals printable' to practise this.

My son's primary school does this place value to saturation in year 5.

He always forgets the next stage along though, to add the total tenths/hundredths, if the question asks, until I roll my eyes and he laughs! So in 1.12 he may say there are two hundredths, as in the amount in the hundredths column.

Don't worry, just like time questions, sooner or later they get it!

Thanks guys.
I think I'll hold off the place values for a short while and try those printables in a couple of months.
Bob

Hi,

Do a Google search for a Gattegno grid.

It should have numbers in lines with 1000ths to 1000s.

I use them a lot for place value. Just point to numbers and ask what it says. Also ask how do I get from here to here by pointing to the same digit in different places, e.g. From 4 to 400 or 4 to 0.4.

It should make sense with the grid.

I wonder if you need to take him back to some very clear principles to answer these questions.

e.g. how many tenths in 1? Answer 10

so how many tenths in 2? Answer 20

What are we actually doing? We are cutting everything up into tenths and the answer is 10 times the number we first started with.

So how many tenths in:

0.5 ---- 5 - yes, and you can see this because there is a number 5 in the tenths column

Do the same with hundredths

Same with thousandths

Until he can see that you need to multiply by 10 to find out how many tenths, multiply by 100 to find out how many 100ths, multiply by 1000 to find out how many 1000ths etc etc.

He should then easily be able to do it for any number you give him.

Do it over the summer.

Also do it with money. e.g. how many lots of 10 pence in £5.60? Multiply by 10 because 10pence is one tenth of a pound. How many pennies in £5.60? Multiply by 100 because 1p is one hundredth of a pound.

And also do it all in the other direction. How many tens in 563700? Are you going to divide by 10 or multiply by 10? How many hundreds is the digit in the thousand columns worth? Find its value to start with - 3000. Now are you going to divide or multiply by 100?

etc etc

It is not too soon.