Adding tens and hundreds

the first pattern was counting by tens and the second pattern was counting by hundreds. We are going to use place value to help us add by tens and hundreds today!

Let's practice adding by ten first.

I want to add 250 + 10 = _

First, you use your flats and rods to represent the number 250.

Here is the number 250 modeled using flats and rods. There are 2 hundreds, 5 tens, and 0 ones.

Now that we modeled 250 using flats and rods let's add 10 more. When we add 10 to a number we are only adding 1 ten to the tens place. 5 tens plus 1 ten equals 6 tens. 250 + 10 = 260.

Now we are going to practice adding a hundred.

I want to add 222 + 100 =

First use your flats, rods and units to represent 222.

There are 2 hundreds, 2 tens, and 2 ones. We are adding 100 to 222. This means we only need to add 1 hundred to the number in the hundreds place. The numbers in the tens and ones place will stay the same

Now that we modeled 222 using the flats, rods and units, let's add 100 more.

We have added a flat, or 100, to the number 222. We added 0 ones, so the ones place stays the same. We added 0 tens, so the tens place stays the same. We added 1 hundred to the hundreds place, so 2 + 1 = 3. Adding 1 to the hundreds place gives us 322.

So, 222 + 100 = 322.

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