Learn the essential vocabulary and rules for setting up multi-digit addition problems, including place value and how to line up numbers correctly. This is the first step to becoming an addition expert!
Place value is the value of a digit based on its position in a number. In the number \(285\), the \(5\) is in the ones place, the \(8\) is in the tens place (worth \(80\)), and the \(2\) is in the hundreds place (worth \(200\)).
What is an 'addend'?
An addend is any of the numbers that are being added together. In the problem \(7 + 3 = 10\), both \(7\) and \(3\) are addends.
What is a 'sum'?
The 'sum' is the total or the answer you get when you add numbers together. In the problem \(7 + 3 = 10\), the number \(10\) is the sum.
In the problem \(123 + 456\), which numbers are the addends?
The addends are \(123\) and \(456\).
What is the most important first step when adding multi-digit numbers like \(251 + 63\)?
Line up the numbers vertically so that their place values are in the same columns. Ones should be above ones, tens above tens, and so on.$$\begin{array}{rr}
& 251 \\
+ & 63
\end{array}$$
Why is it important to line up numbers by place value before adding?
To make sure you are adding ones to ones, tens to tens, and hundreds to hundreds. If you don't, you will get the wrong answer.
When adding numbers in columns, which place value do you always start with?
Always start with the column on the far right, which is the ones place.
Starting from the right, what are the names of the first three place value columns?
1. Ones place
2. Tens place
3. Hundreds place
How would you correctly stack the numbers to solve \(345 + 52\)?
Place \(345\) on top. Place \(52\) underneath, making sure the \(2\) is under the \(5\) (ones place) and the \(5\) is under the \(4\) (tens place).$$\begin{array}{rr}
& 345 \\
+ & 52
\end{array}$$
