# Addition - using Partial Sums Method

Videos, stories and songs to help Grade 2 students learn how to add using the partial sums method and how to subtract using the trade-first subtraction method.

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How to add using the partial sums method?

1. Starting from the left, add up the numbers in the hundreds place.
2. Add up the numbers in the tens place.
3. Add up the numbers in the ones place.
4. Add up all the partial sums.

Some advantages of using the partial sums method:

1. The method breaks down the addition process into clear, step-by-step calculations. This approach can help students avoid errors and maintain a structured method for solving problems..
2. Partial sums method emphasizes the importance of place value. Students can clearly see how each place value contributes to the overall sum, reinforcing their understanding of the base-10 system.
3. The partial sums method can be a precursor to the standard algorithm for addition. Understanding the partial sums method can make it easier for students to transition to the standard algorithm when they are ready.

How to subtract using Trade-First Subtraction Algorithm?

1. Look at the digit in the 1s place. If subtracting these digits results in a negative number then trade 1 ten for 10 ones.
2. Do the same for the 10s place, 100s place and so on.
3. Subtract in each column.

3 digits + 3 digits using the partial sums addition method