The work on subtraction facts in year 3 is very similar to that in year 2. Constant practice and re-enforcement is necessary if children are going to become quick in their responses- the numbers do not necessarily have to be larger, but a more rapid answer should be expected. A similar list of words and phrases should be used as for year 2, including: take away,   subtract,   how many are left,   less than, what is the difference between,   more than,  how many more to make …. It is expected that the minus (–) sign can be read and written. Most of the work will still be done orally. All kinds of opportunities arise where simple subtraction questions can be posed, but, again, the numbers do need to be kept simple. A number line or a number square is useful for harder examples so that children can see the  movement down the line as numbers are subtracted. Coins, counters or cubes are also excellent resources for practical subtraction exercises. Children should understand that subtracting from a positive number makes the number less and that subtraction is the opposite, or inverse of, addition. The idea that subtracting 0 leaves a number unchanged also needs to be re-enforced and children need to realise that 40  –   30  is not the same as  30  –  40. Subtraction - oral questions Examples of the type of question to ask include: 1. What is 30 take away 12 ? 2.  Take 14 from 40. 3.  60 subtract 41. 4.  What is 12 less than 40  ? 5. What number must I take from 30 to leave 9  ? 6. What must I add to 13 to make 50 ? 7. What is the difference between 11 and 50  ? 8.   How many more is 60 than 18  ? 9. 17 taken from a number is 23. What is the number? 10.  60 added to a number is 84. What is the number? 11. Find a pair of numbers that have a difference of 41. 12. Find two numbers which have a difference of 33. Children continue to be expected to work out more complex subtraction in their heads. Subtracting 19, 29, 39 etc from any two digit number is the next step e.g. 58 - 29. Because it is usually easier to subtract whole tens or a single digit the most effective method involves several steps: 58 - 29 1. adjusting the second number to the nearest whole ten: e.g. 29 to 30 2. subtracting the 30 from 58 leaves 28 3. readjusting by adding 1 makes 29. 58 – 29 = 29 Subtracting a single digit from a multiple of 100 is also introduced eg 300 – 5. This some children find quite difficult and they need to be confident in counting up and down crossing the hundreds boundary. Other skills taught will include: subtracting a pair of multiples of 100 crossing 1 000   eg 1 300 – 500 subtracting 100 from any three digit number Finding small differences between two numbers either side of 100 is extended to multiples of 100, up to 1 000. Written methods In year 3 children are encouraged to make jottings to help them with more difficult subtractions, leading to a more efficient method later. Three different approaches are suggested, each one reliant on previously learnt mental methods. At first children need to practice the methods, even though they may be confident enough to find the answer without resorting to pencil and paper jottings. To find out more about the three methods click the link below. Go to the Year 3 subtraction pages