Lesson 14: Greatest and Smallest 200–499
Lesson Objectives
- Extend understanding of place value to 200-499
- Represent place value with concrete and pictorial models
- Use bundles to represent tens through 90
- Show numbers 200-499 with base ten blocks
- Relate place value form, expanded form, and standard number
- Locate and compare numbers on number lines
- Apply patterns in number sequences
Materials
- Extend Workbook (Page 14)
- Place value mat
- Hundreds Chart
- Base 10 Blocks
- Beads and string
- Linking cube manipulatives or other stacking manipulatives
- Open number lines
- Three-digit number cards (if available)
- Whiteboard with dry erase markers and erasers
Step 1: Warm Up (5 min)
Discuss number lines with your students. Tell them they will name the number by its location on a number line and use that number to compare to another number on the line. Review place value within 100-200 and apply knowledge from last lesson to play around with the place value mat, base ten blocks, and a whiteboard (if needed). Have students make numbers within 100-200 with their base ten blocks and place value mats (e.g. 125 is 1 flat, 2 rods, 5 units). Distribute 2 flats, 19 rods, and 9 units to pairs. Reivew that when you have three-digit numbers, you have hundreds, tens, and ones. Play around with variations of numbers 100-200 using the manipulatives.
Step 2: Vocab Review (5 min)
Review number lines, and intervals within a number line, as well as hundreds with place value, rods, flat, counting on, and greater than/less than/equal to. When reviewing 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). Another helpful support 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). Review “equal to”: We use equal to when both numbers are equal or the same.
Step 3: Model (5 min)
Take out an open number line and review the parts of the number line (e.g. 100-110 with eleven total intervals, or “tick marks,” would represent numbers going up by ones: 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110). Play around with numbers 100-200 and counting on the intervals, going up by ones. Practice labeling the intervals (100 and 110 as starting points, 100 being the first number and 110 being the last number). Students can label each interval between 100 and 110). To further support number line understanding, you can conduct this activity – ask 10 students to come forward. Have them stand in a line facing the room. Count as you number each of them in sequence: I will say 100 for the first person, and count from 100 to 110. Each of the 10 of you has a number now. Your first number is 100, except for the last person. Your second number is in sequence starting at 1. What number is the last person? (110). You can ask the middle person to step forward (105) and call out other numbers in that sequence to step forward. Then ask two students to step forward (e.g person 108 and “102”). Is 108 farther up on the number line than 102 (yes), then it is greater than 102, because 102 is lower on the number line. Remind students when value in hundreds place is the same, compare the value in the tens place, and when numbers in the tens place are the same, compare the value in the ones place. Play with the open number line, labeling intervals and comparing numbers.
Step 4: Guided Practice (5 min)
Have students work in pairs or groups. Give students three-digit numbers between 300-499 (e.g. 300-310, 340-350, 460-470) and in their pairs, have students make label each interval in between (there should be 11 total intervals). Students can also practice place value with three-digit numbers between 300-499 (staying within 10 to compare; 320 __ 330, 470__480). Let students work together with their place value mats to compare these numbers.
Step 5: Student Practice (5 min)
Go to Student Workbook Page (14). Using their open number lines, have students copy the first number line on page 14, starting with 300 and ending on 310. Have students label each interval and putting the second interval number in the box (302). Then, have students compare 302 and 305. Ask them, which number comes farther down the line (to the right)? That number is greater than the number (compared to the number on the right). 305 is greater than, or bigger, than 302. Have them place the greater than symbol facing 305 in the oval (review helpful tricks on how to remember which way to face the symbols). Repeat this step for the next four number line problems.
Step 6: Wrap Up (5 min)
Review lesson objectives, key vocabulary words, place value, and counting on.