Lesson 13: Greatest and Smallest 100–199
Lesson Objectives
- Extend understanding of place value to 101-199
- Represent place value with concrete and pictorial models
- Use bundles to represent tens through 90
- Show numbers 101–199 with base ten blocks
- Relate place value form, expanded form, and standard number
- Compare numbers on number lines (optional support)
Materials
- Extend Workbook (Page 13)
- Place value mat
- Base 10 Blocks
- Highlighters, crayons, coloring pencils, or markers
- Linking cube manipulatives or other stacking manipulatives
- Place value mats
- Whiteboard with dry erase markers and erasers
- Open number lines (optional)
Step 1: Warm Up (5 min)
Model hundreds with base ten blocks and a place value mat on the whiteboard. Repeat the activity with pairs of students. Distribute 1 flat, 20 rods, and 10 units to pairs. Review that students have counted to and represented the place value of numbers through 99, and that the next number is 100. Explain that when you have three-digit numbers, you have hundreds, tens, and ones. Play around with variations of numbers 50-99 and also 100.
Step 2: Vocab Review (5 min)
Review hundreds with place value, rods, flat, in addition to counting on, and greater than/less than/equal to. When teaching greater than and less than symbols, go over helpful tricks (e.g. < symbol can look like an “L” for “less than” or smaller; and > symbol is the opposite or “greater than” or more). Remind sutdents to read the compare sentences from left to right (6>2 would be read as “Six is greater than 2”). You can also teacher the open mouth alligator trick: “becuse alligators are always hungry, they always want to eat the bigger number. The open part of the greater than or less than sign always faces the bigger number. For example 6__2. The mouth will open towards the 6 because it is more). Teach “equal to”: We use equal to when both numbers are equal or the same.
Step 3: Model (5 min)
Tell students when they have 10 ones or units, you can exchange them for 1 ten. Now you have traded 10 units for 1 ten. Show students as you count the tens: 1, 2, 3, 4, 5, 6, 7, 8, 9, and when you get to 10, it is not longer a one-digit number in the tens place, just as 1 rod in 10 ones. First number is 20, yes 2 rods. Next number is 50, yes 5 rods. Next number is 99, yes 9 rods and 9 units. Next number is 100, yes 1 flat. Build numbers through 100 and beyond. Show examples of various numbers with 1 flat, rods, and units (e.g. 110, 125, 146). Next, practice with number comparisons (review helpful tricks in the vocabulary section). Another helpful trick is the “dot” trick. Place dots on points the greater than/less than symbols (3 total). The two dots face the greater number and the one dot faces the smaller number (you can also color code the two dots versus the one dot).
Step 4: Guided Practice (5 min)
Have students work in pairs. Give students numbers and in their pairs, have students to place the numbers in their place value mat and to tell each other the place value of the number [e.g. 109 is 1 hundred (or 1 flat) + 0 tens (or 0 rods) + 9 ones]. Go through a few examples all together before having them work in pairs together. Once they have practiced with place value with three-digit numbers, write down two different numbers within 100-200 on the whiteboard (with place value cues/supports) and work on comparing/contrasting with students (e.g. 101 __ 115, 150__170). Then, let students work together with their place value mats to compare different numbers between 100-200.
Step 5: Student Practice (5 min)
Go to Student Workbook Page (13). Using their place value mats and base 10 blocks, have students create both number (101 and 110). Then, have students place the correct symbol in between the 101 and 110. Following this, have them write the symbol on their student activity page. Repeat this step for the next four problems.
Step 6: Wrap Up (5 min)
Review lesson objectives, key vocabulary words, place value, and counting on.
