Converting Fractions to Decimals Lesson 5 2 AMSTI

Converting Fractions to Decimals Lesson 5. 2 AMSTI 2006

Video Lets watch a video to preview how to convert fractions to decimals, the Egyptian way!

Converting Fractions to Decimals n To convert a Fraction to a Decimal manually, follow these steps: n Step 1: Find a number you can multiply by the bottom of the fraction to make it 10, or 1000, or any 1 followed by 0 s. n Step 2: Multiply both top and bottom by that number. n Step 3. Then write down just the top number, putting the decimal place in the correct spot (one space from the right for every zero in the bottom number)

Method #1: Converting with Proportions n Example # 1: Express 3/4 as a Decimal n Step 1: We can multiply 4 by 25 to become 100 n Step 2: Multiply top and bottom by 25 3 = 75 4 100

Example # 1 continued…. n Step 3: Write down 75 with the decimal place 2 spaces from the right (because 100 has 2 zeros); n Answer = 0. 75 Can you explain what we just did? n Try to express ¼ as a decimal using method # 1. n

Method #2: Convert by Dividing § Example #1: to write 5/8 as a decimal, we need to calculate 5 ÷ 8: 0. 625 8 √ 5. 000 So = 0. 625 as a decimal. § Try this example: write 4/5 as a decimal using division (method #2).

Remember… n To change a fraction to a percentage follow the rules for fraction to a decimal and then multiply by 100. n Or use the magic square! Part Variable – Cross multiply Whole 100

Lets Practice!! n We are going to use this website to fish out some fractions and decimals. n Lets see how well you understand this lesson. n Go to www. iknowthat. com n Select “Math” in the left margin n Select “Fishy Fractions” n Select “Fractions and Decimal Match”