Revising subtracting small numbers with the help of a number line.
This time there’s a number square to help with subtraction. It’s interesting to see how children use the number square to help them.
Taking 15, 16, 17 or 18 from 2-digit numbers. The easiest way of doing this is by taking a whole ten and adjusting.
Children can show how quickly they can calculate mentally by answering these questions as fast as possible.
Finding the difference between two numbers as well as making subtraction number sentences from the numbers given.
Use knowledge to subtract a single digit from a teen number quickly and efficiently. Rather than just counting up in ones, look for two steps, firstly to ten and then to the number.
Remember that subtractions can also be done by subtracting the nearest whole ten and adjusting.
Write a digit in each box so that the calculation is correct. look for patterns.
Try taking away a single digit from a 3-digit number. These include taking away from whole hundreds which can be quite tricky.
Here we have some serious 2-digit addition. On the first two pages the answers all come to just more than 100.
Subtracting 2-digit multiples of 10, often crossing the hundreds boundary
A mixed selection of adding and subtracting multiples of 10.
Now we are on to subtracting multiples of 100, often crossing the thousands boundary.
A mixed bag of subtraction questions, mainly crossing the tens boundary.
Sometimes quite tricky subtractions can be made easy by counting up. Have a look at these to see why.
How to use jottings to help with subtraction: the first stages of moving towards written methods of subtraction.
Subtraction by compensation means taking away more than you need and then adding some back. It can be quite an effective way to subtract.
Subtraction by decomposition is the way most adults are familiar with and is the way that children will ultimately use for larger numbers. Here is an introductory exploration of the idea.