Estimation of Addition and Subtraction of Three-Digit Numbers

This video tutorial provides practice in estimating the addition and subtraction of three-digit numbers. The instructor demonstrates how to round numbers to the nearest ten or hundred to make quick mental calculations. Two examples are provided: one for addition (398 + 251) and one for subtraction (678 - 273). The video emphasizes the importance of estimation in everyday situations, such as shopping, and explains that different reasonable estimates can lead to slightly different results.

What is the primary focus when estimating sums and differences of three-digit numbers?

• Getting the exact answer

• Understanding the concept of estimation

• Using a calculator

• Memorizing the numbers

When estimating 398 + 251, what is the approximate sum when rounding to the nearest ten?

• 600

• 650

• 750

• 700

What is the nearest hundred to 398?

• 300

• 400

• 500

• 600

What is the nearest ten to 251?

• 240

• 250

• 260

• 270

What is the exact sum of 398 and 251?

• 650

• 649

• 651

• 648

When estimating 678 - 273, what is the approximate difference when rounding to the nearest hundred?

• 300

• 400

• 500

• 600

What is the approximate difference of 678 - 273 when rounding to the nearest ten?

• 410

• 420

• 430

• 440

What is the nearest hundred to 678?

• 600

• 700

• 800

• 900

What is the nearest hundred to 273?

• 200

• 300

• 400

• 500

Why is it important to have multiple-choice questions for estimation?

• To ensure everyone gets the same estimate

• To allow for different reasonable estimates

• To confuse the students

• To make the quiz easier