NC.2.MD.6

Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points and represent whole-number sums and differences, within 100 on a number line.

Step 1: Lesson Standards & Learning Goals

Unpacking Clarification

This standard expects students to represent numbers on a pre-marked number line.
- - This standard is intended to be foundational since the number line is pre-marked and given to them. Students should eventually transition to an open number line which they create and draw independently. An open number line is used to provide a visual and show strategies such as breaking apart tens and ones, adding or subtracting in parts to land on landmark (friendly) numbers, or the relationship between addition and subtraction.
This standard expects students to use a number line as a tool to help them find the sums and differences of numbers within 100.
- - These tasks should be embedded in the context of word problems since word problems help students to make sense of the mathematics in the problems (van de Walle et al., 2019).

Sample Essential Questions

How can number lines be used to find sums and differences?

How can a number line help us understand and solve word problems?

Vocabulary

add
addends
difference
distance
equal sign (=)
number line
point
subtract
sum
unknown number
whole numbers

Students will be able to...

Represent numbers on a pre-marked number line.
Use a number line to find sums and differences.
Create number lines with evenly spaced points corresponding to the numbers to solve subtraction problems with differences within 100.
Solve word problems involving addition and subtraction using a number line.

Students will know...

Numbers on a number line increase from left to right and decrease from right to left.
Number lines are divided into evenly spaced intervals.
A ruler can be compared to a number line.
Number lines can begin and end with any range of numbers.
- - For example, a number line can begin with 357 and end with 857 and be separated into evenly spaced intervals of one hundred.

Step 2: Assessment