Basic Column Addition
1. Write out the numbers that are being added together below each other. When adding it doesn’t matter in which order you write the numbers but the units, tens, hundreds etc. must always be in the same column. This method can be used for any size number and to add as many numbers as necessary, however the more numbers there are, the bigger the chance of miscalculating.
2. Firstly, add together the numbers in the units column (right) and write the number below.
3. Finally, add together the numbers in the tens column (next along to the left) and write the number below. We encourage the children to think of this as adding e.g. 4 tens and 2 tens, to reinforce that they are tens not units. If you are solving a sum with more than 2 digits, keep moving along the columns from right to left until all columns have been added.
Column Addition with Carrying
1. As with basic column addition, you need to ensure that first each number is written in the correct column (hundreds, tens & units).
2. We always begin by adding the units column first. 9+7= 16
2. We always begin by adding the units column first. 9+7= is made up of 1 ten and 6 units so we have to carry the 1 ten and put it underneath the tens column. This is because we can only have units in the units column.
3. Now we move onto the tens column
3. Now we move onto the tens column. 8 tens + 4 tens = 12 tens but because we have carried 1 ten over from the units column we need to add this also. We cross it out to show that we have remembered to add it. So now we have 13 tens or 130 (which is 1 hundred and 3 tens). As we now have 1 hundred we put it underneath the hundreds column so that we can add it with the hundreds. The 3 tens are written in the tens column.
5. Finally we add together the hundreds column
5. Finally we add together the hundreds column. 6 hundreds + 5 hundreds = 11 hundreds. Remember we add the 1 hundred that we carried from tens column and cross it out. This now make 12 hundreds (1200 or 1 thousand and 2 hundreds). The 2 hundreds are written in the hundreds column and the thousand it written next to it. If you are solving a sum that is 4 digits the 1 thousand would be written underneath the thousand column like when carrying the other numbers but because there are no other columns it is written next to it.
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