Let’s Learn!

We can help Casey and Landon by subtracting 300 from 800. 800 is the whole, and 300 is the part. Our first step is to stack these numbers.

Now that the whole and part are stacked, let’s add a subtraction sign and a line.

Great job! The digits in the ones and tens places are zeros. Try ignoring these digits to make subtraction easier!

Now it is time to subtract the digits in the hundreds place. What is 8 - 3?

We already know that 0 - 0 = 0, so write the zeros in the difference.

See how easy it is to subtract hundreds when we ignore the zeros? This is a mental math strategy. Mental math is math that you do in your head, without paper or pencil. Let’s check our work on a thousand chart. A thousand chart lists numbers from 10 to 1,000 in multiples of ten.

Show Me

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Our difference is correct! 800 - 300 = 500.