Adding Two Digit NumbersIn math we are beginning to learn to add two digit numbers by combining tens and ones. This is a strategy based on place value that many people use to mentally add numbers. In order to accomplish this skill, it is important that students have a solid understanding of place value and a level of automaticity with their basic addition facts. If your child is struggling to automatic recall of basic facts (up to a sum of 20), please help him/her practice at home.
We will not be using the standard method of adding multiple digits YET. We will also be focusing on equations that do not require regrouping (aka carrying). Below is an example of how solving an equation might occur. As a first step, we will be using base ten rods to build and combine numbers. We will then move to using expanded notation. Finally, we will end up at the traditional method of adding 2 digit numbers.
23 + 56
step 1. expand the numbers: 20 + 3 50 + 6
step 2. add the ones, add the tens: 6 + 3 = 9; 20 + 50 = 70
step 3. combine the tens and ones: 70 + 9
This learning and practice will help to prepare students for the more traditional paper and pencil method of addition in the future. However, it is crucial that they develop a solid understanding of the concept prior to memorizing the procedure.