Here are some more pages for practising wthe written method of subtraction, but with nice easy small numbers. This method of subtraction is often known as decomposition. Usually it should be used when numbers are too large or too awkward to subtract mentally. Remember: mental methods should be the first resort. However, to get a better idea of this system it is probably best to keep to small, 2-digit subtraction to begin with. Looking at a question such as 74 - 39. It would firstly need to written in a vertical format, with units under units and tens under tens. Step 1: look at the units and adjust if necessary 4 - 9 does not give a positive answer so an adjustment needs to be made. Adjust 10 from the tens to the units. This makes the tens one 10 less and makes the units 10 more. Cross out the 7 tens and make it 6 tens. Put the extra 10 in the units, making the 4 units 14 units. Step 2: subtract the units 14 (units) - 9 (units) = 5 (units). Put the 5 in the units, in the row below, making sure the units line up. Step 3: subtract the tens 6 (tens) – 3 (tens) = 3 (tens) Put the 3(tens) in the tens column. Remember only adjust or ‘decompose’ when necessary! A clearer explanation is on the first page, which can be found in the Year 4 subtraction worksheets. Go to: More written subtraction of 2-digit numbers