Читать книгу Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online) - Mark Zegarelli - Страница 48

To round numbers to the nearest hundred, thousand, or beyond, focus only on two digits: the digit in the place you’re rounding to and the digit to its immediate right. Change all other digits to the right of these two digits to 0s. For example, suppose you want to round 642 to the nearest hundred. Focus on the hundreds digit (6) and the digit to its immediate right (4):

I’ve underlined these two digits. Now just round these two digits as if you were rounding to the nearest ten, and change the digit to the right of them to a 0:

Here are a few more examples of rounding numbers to the nearest hundred:

When rounding numbers to the nearest thousand, underline the thousands digit and the digit to its immediate right. Round the number by focusing only on the two underlined digits and, when you’re done, change all digits to the right of these to 0s:

Even when rounding to the nearest million, the same rules apply:

1 Round the following numbers to the nearest ten:

(a) 83

(b) 217

(c) 1,885

(d) 6,496

2 Round the following numbers to the nearest hundred:

(a) 347

(b) 2,251

(c) 7,950

(d) 39,974

3 Round the following numbers to the nearest thousand:

(a) 6,543

(b) 9,287

(c) 22,501

(d) 799,643

4 Round the following numbers to the nearest million:

(a) 5,454,545

(b) 10,730,421

(c) 98,765,432

(d) 5,555,555,555