Lesson 12: Quantities and Expanded Form 51–99
Lesson Objectives
- Count orally to 99
- Count on from any number
- Associate the number of objects with the numeral
- Represent numbers with pictures
- Use numerals as abstract representations of numbers
Materials
- Extend Workbook (Page 12)
- 100s Chart
- Highlighters, crayons, coloring pencils, or markers
- Linking cube manipulatives or other stacking manipulatives
- Beads and strings
- Place value mats
- Whiteboard with dry erase markers and erasers
- Straws and rubber bands (optional)
Step 1: Warm Up (5 min)
Practice skip counting by fives and tens, using a hundred chart. Practice counting with student ages as a starting number, adding 10 to each number in sequence. Practice throwing a ball in a group, counting from a given number. Practice counting aloud from a given number to a given number of steps.
Step 2: Vocab Review (5 min)
Count on, sequence
Step 3: Model (5 min)
Pull out a 100s chart review all tens (10, 20, 30) for support. Take your linking cubes, work through grouping five groups of 10 to make 50, then add in extra objects to represent numbers 51-59. Continue making another sets of 10 and adding in ones to make larger numbers up to 69. Continuing adding in another set of 70 and adding in ones to represent a number in the 70s. Continue this sequence for a number in the 80s and 90s. Draw eight groups of 10 (e.g. stars) on a white board and circle the groups of 10. Then draw 5 stars outside of the circle to represent 85, and then another star to represent 86.
Step 4: Guided Practice (5 min)
Tell students that they have represented numbers 1-99 in many ways, and they all show the place value of the number. It is 10 objects, or 1 bundle of 10 and ones on the place value chart. It is a two-digit number: tens and ones. Give students different manipulatives to play around with and work with students to make bundles of 10 (e.g. 50, 60, 70, 80, 90), then so many extra to make numbers 51-99. Students may also use white boards and draw groups of 10, circling the group and making so many extra outside of the circle to represent numbers 50-99.
Step 5: Student Practice (5 min)
Go to Student Workbook Page (12). Have students link 10 linking cubes together to represent one group of 10, and continue making groups of 10 to match the first number in the tens column (70). Then tell them to count the number of linking cubes in the ones column (6). Students can write 76 next to the first tens/ones place value, then draw a line to connect it to 76 in the box. Repeat steps for the next four numbers (67, 89, 99, 83).
Step 6: Wrap Up (5 min)
Review lesson objectives, key vocabulary words, place value, and counting on.