1. Presented by Robin Seldin
Partial Sums
Presented by
Robin Seldin

2. When students begin to learn how to add two-digit numbers they are usually taught “carrying”.
A different way to do this is called the “Partial Sums” algorithm.
Partial sums focuses on place value when solving two-digit addition problems.
It teaches children to start on the left and add the tens first.
Moving from left to right (just like in reading!) actually makes sense to the children and they have a better understanding of why and how they get their answer.

3. Here is an example of the Partial Sums Algorithm:
4 5
+ 3 8
7 0 Step 1: Add the tens ( = 70) and write the sum Step 2: Add the ones (8 + 5 = 13) and write the sum.
8 3 Step 3: Add the tens and ones
( = 83) to get the final answer.

4. Here is another example of the
Partial Sums Algorithm:
6 7
+4 5
100 Step 1: Add the tens ( = 100) and write the sum Step 2: Add the ones (7 + 5 = 12) and write the sum.
112 Step 3: Add the tens and ones
( = 112) to get the final answer.