Lesson 20: Addition within 99
Lesson Objectives
- Review Touching/Counting Patterns for numbers 1-9
- Apply understanding of place value to add within 99 without regrouping
- Use visual cues to aid in addition algorithms
- Apply TouchPoints on lesser numerals
- Identify pairs of numbers whose sum is within 99
- Use TouchPoints as a strategy in computation
- Join together groups of objects to add
- Add using Pictorial TouchPoints
- Count on using TouchPoints
Materials
- Extend Workbook (Page 19)
- Counters or manipulatives
- TouchMath’s Foam Numerals with TouchMath’s TouchPoints with or without pictures
- TouchMath’s number line
Step 1: Warm Up (5 min)
Give students practice single-digit addition problems and review strategies from prior lessons: 1) identify the larger number using the TouchMath number line, 2) cross the larger number out while saying it aloud, 3) count on the TouchPoints of the other addend to find the sum. After reviewing a few problems, show a double-digit addition problem (without regrouping) and explain that they will be doing what they just did but now with two-digits.
Step 2: Vocab Review (5 min)
Review prior vocabulary: addends, addition, addition sign, equals, sum, counting on, and unknowns. Review the visual cues of the columns to help students “stay in their lane,” and “to start on the side with the arrow.”
Step 3: Model (5 min)
When modeling double-digit addition without regrouping, remind students to start on the side with the arrow in the ones column, and then go through the usual steps: 1) identify the larger number using the TouchMath number line, 2) cross the larger number out while saying it aloud, 3) count on the TouchPoints of the other addend to find the sum. Then, have them move on to the left column in the tens place and follow the same steps. Afterwards, repeat the entire problem (e.g. “23+31=54”), as this will help students to practice saying larger numbers aloud.
Step 4: Guided Practice (5 min)
After modeling practice problems with your students, ask students to volunteer to show the correct steps when adding double-digit numbers without regrouping. Students can also take turns in pairs or in groups and see if students can get all the steps down without help.
Step 5: Student Practice (5 min)
Go to Student Workbook Page (20). Read the directions at the top of the page. Tell students they will answer the problems to solve the riddle at the bottem. Based on the sum of their answers, find the matching sum at the bottom and write its corresponding letter there. Review the first 1-2 problems with students, reviewing the correct steps: 1) start on the ones side with the arrow, 2) identify the larger number using the TouchMath number line, 2) cross the larger number out while saying it aloud, 3) count on the TouchPoints of the other addend to find the sum. Repeat these steps in the tens column, and then repeat the entire problem (e.g. “61+27=88”), as this will help students to practice saying larger numbers aloud. Write the letter “n” above the 88 number at the bottom of the page. Work through each problem until students have finished the riddle.
Step 6: Wrap Up (5 min)
To wrap up the lesson, review the learning objectives and core vocabulary words again and ask your students about their experience.
