By Elena and Jordan

When you are doing place value you need to pay attention to the number columns. For example,
H T O
1 2 5
Place value is like looking where the numbers are placed in the columns. If there is a one in the hundreds column, it becomes a hundred, a two in the tens place and it becomes twenty, but numbers in the ones column stay the same.
Place value can be used for a bigger number too.

Expanded notation is when you stretch a number out. For example, if you had the number 125, the expanded version would be 100+20+5. You can expand numbers that are higher as well;
1,257=1000+200+50+7.
If you had the number 12,593, there are two ways to expand it. One way is to do it like this; 12,000+500+90+3, but you can expand it more, 12,000 is made up of
10000 and 2000, so the other way is
10000+2000+500+90+3. Those are the different ways.

Trading is what happens when you do addition. When you look in the ones column of the numbers you are adding and they equal more than ten you have to trade. For example,
645
+126
Five plus six is eleven, so that ’ s is more than ten. So you have to move the ten into the tens column, and keep the remaining one in the ones place.

Once you have moved the ten the sum should look like this:
64 ’ 5
+126
1
The small line above the 4 represents the extra ten. Under the ones column is the answer one. Now look at the tens column. 40+20=60, but when you add the extra ten it becomes 70, so put a seven under the tens column for an answer.

Now the sum should look like this:
645
+126
7 1
Now look at the hundreds column.
600+100=700, so put another seven under the hundreds column for an answer.
645
+126
7 7 1
So the total answer is 771!

Everything by Elena and
Jordan!