Difference between revisions of "Long addition"
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| + | '''Long addition''' is a simple, fairly long winded, but highly useful method of adding multi-digit [[number]]s together. | ||
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| + | Imagine that we are adding 205 to 876. | ||
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| + | *Firstly, write the numbers above each other. Make sure that the digits of both numbers are clearly aligned according to their place values (i.e. ''hundreds, tens and units''). Leaving a definite space between your columns helps avoid confusion, especially with larger sums. | ||
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| + | *Then, it is as simple as adding the columns. Begin in the units column and work from right to left. | ||
| + | *In our example, adding 5 and 6 gives 11. 11 can be thought of as 1 ten and 1 unit. The unit is recorded in the answer box in the units column. The ten must be "carried" into the tens column, so the next operation is 7 + 0 ''+ 1'' = 8. The eight is recorded in the answer box in the tens column.<ref>Properly speaking, this operation is 70 + 0 ''+ 10'' = 80.</ref> | ||
| + | *Finally, we add the digits in the hundreds column (8 + 2 = 10).<ref>Similarly, 800 + 200 = 1000.</ref> The zero is recorded in the answer box in the hundreds column, and the one is placed in the answer box in a new thousands column. | ||
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| + | <center> | ||
[[Image:Picture8ol0.png]] | [[Image:Picture8ol0.png]] | ||
| + | </center> | ||
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| + | ==Footnotes== | ||
| + | <references/> | ||
| + | [[Category:Mathematics]] | ||
Latest revision as of 02:43, November 25, 2008
Long addition is a simple, fairly long winded, but highly useful method of adding multi-digit numbers together.
Imagine that we are adding 205 to 876.
- Firstly, write the numbers above each other. Make sure that the digits of both numbers are clearly aligned according to their place values (i.e. hundreds, tens and units). Leaving a definite space between your columns helps avoid confusion, especially with larger sums.
- Then, it is as simple as adding the columns. Begin in the units column and work from right to left.
- In our example, adding 5 and 6 gives 11. 11 can be thought of as 1 ten and 1 unit. The unit is recorded in the answer box in the units column. The ten must be "carried" into the tens column, so the next operation is 7 + 0 + 1 = 8. The eight is recorded in the answer box in the tens column.[1]
- Finally, we add the digits in the hundreds column (8 + 2 = 10).[2] The zero is recorded in the answer box in the hundreds column, and the one is placed in the answer box in a new thousands column.
