Year 6

We can divide numbers with up to 2 decimal places by one-digit and two-digit numbers using efficient written methods

Year 6 Unit 11c

What we are learning:

We are now using the same method of long division but we are including decimals as well.
If we have 154.4 ÷ 4 we set it out in the same way, being careful to use the decimal point in the correct place:

We can now start dividing in the normal way with multiples of 100 or 10.
If we ask ourselves how many times 4 will go into 154 we know that it will not go 100 times as 4 x 100 is 400. We know that 4 x 4 = 16 so 4 x 40 is 160 which is just a little too much, so we try 4 x 30 which is 120.
We enter it like this, as we did before:

We enter the 3 into the tens column of the quotient to represent the 30 x 4 and put the 120 under the dividend and subtract to see how many we have left to divide.
We now have 34.4 to divide by 4. We know that8 x 4 is 32 so we can enter this like this:

We enter the 8 into the units column of the quotient and the 32 under the remaining dividend and subtract.
Now we have 2.4 to divide by 4. If we use our tables knowledge and we can divide by 10 we know that 4 x 6 is 24 so 4 x 0.6 is 2.4. we have to put the decimal point into the quotient, which lets us put the 6 into the tenths column, representing 0.6 like this:

We can now see that 154.4 ÷ 4 is 38.6
Remember that the decimal points have to stay vertically above one another to ensure that every digit in the calculation keeps its correct value.

Extension Activity example – removing remainders when dividing decimals

When we are dividing decimals we do not allow remainders as we can keep dividing to decimal places until we get a complete answer. We do this by adding a zero into the next column on the right to keep dividing. Adding these zeros does not change the value of the dividend (the number we are dividing. An example is 138.2 ÷ 4

We set it out as above and divide it through like this as normal:

The challenge now is that the ‘answer’ appears to be 34.5 with a ‘remainder’ of 0.2
To get rid of the 0.2 we can keep dividing. First we add a zero into the hundredths column of the dividend like this and drop it down onto the end of the 0.2 so that instead of two tenths we have twenty hundredths. Note that two tenths and twenty hundredths have exactly the same value, so we have not changed the number at all.

We can now divide 4 into 20 hundredths and which goes five times. We can now complete the division like this.

We have now divided the whole dividend with no remainder and the answer is 34.55

Activities you can do at home:

Try the divisions in the Activity Sheet. These will all divide with no remainder.

Good questions to ask:

When might we need to divide numbers with decimals? (Think about dividing money or measurements of length)

If your child:

Does not remember to put the decimal point in all the time
Ask your child to read out the number where the decimal point is missing – this should remind them that they need to put it in. If they are still not sure look together at the dividend (the number you are dividing) and identify which column is which. All the other rows in the calculation need a decimal point in the same place.