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## 3rd grade foundations (Eureka Math/EngageNY)

### Course: 3rd grade foundations (Eureka Math/EngageNY) >Unit 2

Lesson 4: Topic D & E: Foundations

# Adding and subtracting on number line

Sal adds and subtracts numbers like 585 and 368 using a number line. Numbers used in these problems are less than 1000.

## Want to join the conversation?

• Can you subtract 54-65? Can you? If you can, what is the answer?
• 54-65 would create a negative number

50-60 = -10
4-5 = -1
-10 + -1 = -11
• What’s a number line?
(1 vote)
• A number line is a graphical representation of numbers along a straight line. It is used to visualize the relative position and magnitude of numbers, as well as to perform operations such as addition and subtraction. The number line typically starts with zero in the center, with negative numbers to the left and positive numbers to the right.
• What does 256 round to the nearest 10?
• Look at the digit just to the right of the tens digit, that is, the units digit. This digit is 6.

6 is 5 or greater, so round up. Add 1 to the tens digit. Change all digits to the right of the tens digit to 0's.