Читать книгу Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online) - Mark Zegarelli - Страница 74

In Chapter 3, I show you how rounding numbers makes large numbers easier to work with. In that chapter, I also introduce ≈, which means approximately equals.

For example,

You can also use ≈ when you estimate the answer to a problem:

Q. Place the correct symbol (=, >, or <) in the blank:

A. <. Because is less than 5, use the symbol that means is less than.

Q. Place the correct symbol (=, >, or <) in the blank:

A. >. Because and is greater than 20, use the symbol that means is greater than.

Q. Sam worked 7 hours for his parents at $8 an hour, and his parents paid him with a $50 bill. Use the symbol ≠ to point out why Sam was upset.

A. Sam worked 7 hours for $8 an hour, so here’s how much he earned:

He was upset because his parents didn’t pay him the correct amount:

Q. Find an approximate solution to

A. 8,000,000. The two numbers are both in the millions, so you can use ≈ to round them to the nearest million:

Now it’s easy to add

15 Place the correct symbol in the blanks:

(a)

(b)

(c)

(d)

16 Change the ≠ signs to either > or <:

(a)

(b)

(c)

(d)

17 Tim’s boss paid him for 40 hours of work last week. Tim accounted for his time by saying that he spent 19 hours with clients, 11 hours driving, and 7 hours doing paperwork. Use ≠ to show why Tim’s boss was unhappy with Tim’s work.

18 Find an approximate solution to 10,002 − 6,007.