ADDITION AND SUBTRACTION
Adding and subtracting is not something we have started doing now and so I do believe that by now most of you know how to do it without needing help. However there are some important tips that you must never forget:
1. When you have two 2-digit numbers, you should always split up your numbers according to their place value, for example:
For addition
25 + 47 = 20 + 40 = 60
5 + 7 = 12
So, 60 + 12 = 72
For subtraction
47 - 25 = 40 - 20 = 20
7 - 5 = 2
So, 20 + 2 = 22
2. If you have more than two 2-digit numbers, you should always use the 'bridge' as we have called it in class. First work out the first two numbers and then add the total to the last number.
3. It is not a bad idea to learn which two numbers when added together always make up a 10, like for example:
1 and 9
2 and 8
3 and 7
4 and 6
5 and 5
Knowing and remembering these will make life easier when you want to add numbers!
Well, now you can do some more work on your own by clicking on the following links:
Little animals
Add and Subtract
Jetski addition
Island chase
Tug team
Alien addition
Minus mission
1. When you have two 2-digit numbers, you should always split up your numbers according to their place value, for example:
For addition
25 + 47 = 20 + 40 = 60
5 + 7 = 12
So, 60 + 12 = 72
For subtraction
47 - 25 = 40 - 20 = 20
7 - 5 = 2
So, 20 + 2 = 22
2. If you have more than two 2-digit numbers, you should always use the 'bridge' as we have called it in class. First work out the first two numbers and then add the total to the last number.
3. It is not a bad idea to learn which two numbers when added together always make up a 10, like for example:
1 and 9
2 and 8
3 and 7
4 and 6
5 and 5
Knowing and remembering these will make life easier when you want to add numbers!
Well, now you can do some more work on your own by clicking on the following links:
Little animals
Add and Subtract
Jetski addition
Island chase
Tug team
Alien addition
Minus mission
