第八课：Multi-digit Addition 多位数相加
ones place 个位
tens place 十位
hundrends place 百位
pus sign 加号
column 列
In this video,we’re going to learn about multi-digit addition.
A multi-digit number is just a number with more than one digit,which is anything greater than 9.Two digit numbers use two number places,like the number 32,it has 2 in the ones place and 3 in the tens place.
But no matter how many digits the number has,if you know your basic addition facts,you can add it to any other multi-digit numbers easily.
Take 215 32 for example.
The first thing we need to do is stack the numbers up.By that,I mean re-writing them so they’re on top of each other.Don’t be sloppy.Make sure they lined up nice and straight.
Here’s the most important part.
Be sure to line up the number places so that they’re directly over each other.
After all the numbers are lined up,draw a line just below the bottom number because our answer is going to go below that.
We also put a plus sign down here on the left sign to show that we are adding.
By stacking the numbers up,we form columns for each number place and we’re going to add the digits in each column.
And this is super important:we always start with the ones place column and work our way to the left.
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