Topics
2. Addition
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United States of AmericaTennessee
Grade 3

2.05 Estimation first

Lesson
Practice
Lesson

Are you ready?

Do you remember how to round numbers? Give this problem a try. 

Round $54$54 to the nearest ten.

Learn

Let's see how we can estimate the answer to an addition problem by rounding the numbers first.

Apply

Choose the right answer.

  1. $143+33$143+33 will be in the:

    $100$100s

    A

    $200$200s

    B

Remember!

We can use number lines to help when rounding numbers. By putting the number in our question on a number line, we can see the closest number. Once we round the numbers in our question, we can then add them together to get an estimate of our answer.

Outcomes

3.OA.D.8

Solve two-step contextual problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding (See Table 1 - Addition and Subtraction Situations and Table 2 - Multiplication and Division Situations).

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