Place value and decimal places

Speaker: Where a digit sits within a number tells you its value. Its place value.

If it's a unit, a ten or a hundred, the position gives the digit a different value.

This flat is for sale for £147,999.

So that's 100,000, 40,000, 7000, 900, 90 and 9 pounds.

Because the 1 is in the hundred thousands position, the 4 is in the tens of thousands position, the 7 is in the thousands position, the 9 is in the hundreds, this 9 is in the tens and this 9 is in the units.

And say this number had a decimal point in it, like .99 - we see this a lot in shops.

The numbers after the decimal point are tenths and hundredths.

Speaker: Understanding place value means you've got an easy way to multiply by 10.

You simply move all the digits one to the left.

So this notebook cost £4.99. But if I bought 10 of them I could multiply £4.99 by 10 by moving the 4 to the tens position, the two 9s to the left, and putting a 0 in the hundredths.

So 10 notebooks would cost £49.90.

And if I want to divide by 10 then I move the digits the other way, to the right.

So my 10 pack of pens at £1.40… divide by 10 to get the price of 1 pen.

1 unit becomes a tenth, 4 becomes a hundredth. So each pen is £0.14.

14 pence.

Speaker: These prices here have the same digits in them.

But the 0 is in a different place.

So the 5 here is 5 tenths, and the 0 is hundredths. So that's 50p.

And then here, 0 tenths and 5 hundredths. So that's 5 pence.

So this one is cheaper than this one. Right, that's the one I'm having.