Lesson objective: Solve real world addition and subtraction problems using the number line in order to compare numbers.

This lesson provides an opportunity for students to apply their knowledge and understanding of finding meaning for comparisons to a real life situation. Students are asked to compare the points scored by four basketball players during a season. Using a set of questions the coach and his players created, students will compare scores and write comparison statements about the points scored.

Key Concept students will use:

- We can compare known quantities by finding the unknown value.

Skills students will use:

- add and subtract numbers within 100 using our knowledge of place value.
- find unknown values in addition and subtraction situations using the relationship between addition and subtraction
- compare two two-digit numbers. (Grade 1, Unit 13)

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they notice that they can use the properties of operations and the relationship between addition and subtraction to solve comparison situations using the number line. Students also engage in Mathematical Practice 7 (Look for and make use of structure) as they utilize their knowledge of number sequence when comparing two numbers using “more” and “less" than.

**Key vocabulary:**

- addend
- addition
- between
- compare
- comparison
- comparison statement
- distance
- equation
- greater than
- less
- less than
- missing number
- more
- number line
- sequence
- subtraction
- tape diagram
- two-digit number
- unknown number
- visual model

**Special materials needed:**

- white boards/markers or paper/pencil
- open number lines