Estimating Sums and Rounding Techniques

In this video, Miss B teaches how to round numbers to estimate sums. The lesson begins with an introduction to the concept of rounding for easier mental addition. Miss B demonstrates the process through multiple examples, using a rhyme to help remember rounding rules. She shows how to round numbers to the nearest ten or hundred and then add them to find an estimated sum. The video concludes with a recap of the steps and a final example, encouraging viewers to practice the method.

What is the first step in estimating the sum of numbers by rounding?

• Multiply the numbers.

• Subtract the numbers.

• Round each number.

• Add the numbers directly.

According to the rhyme, what should you do if the digit is five or greater?

• Leave it as is.

• Multiply by two.

• Subtract one.

• Add one more.

If you round 87 using the rhyme method, what does it become?

• 95

• 90

• 80

• 85

What is the estimated sum of 87 and 34 after rounding?

• 110

• 140

• 120

• 130

When rounding 302 to the nearest hundred, what is the result?

• 200

• 300

• 400

• 350

What is the estimated sum of 302 and 456 after rounding?

• 700

• 750

• 800

• 850

In the alternative rounding method, what do you do if a digit is closer to zero?

• Add zero.

• Subtract one.

• Add one.

• Multiply by ten.

Using the alternative method, what is 52 rounded to?

• 50

• 55

• 60

• 45

What is the estimated sum of 790 and 112 after rounding to the nearest hundred?

• 800

• 950

• 900

• 1000

What is the actual sum of 790 and 112 before rounding?

• 910

• 920

• 902

• 900