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Wonderful world of Decimals 

Wonderful world of Decimals . What is a decimal number?. Think about money. A decimal is a part of a whole . 1 dollar and 4 dimes. 1.40$. Part of the whole. Whole . On a number line. 1. 4. 0. Converting from fraction to Decimal. THERE ARE 2 WAYS

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Wonderful world of Decimals 

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  1. Wonderful world of Decimals 

  2. What is a decimal number? • Think about money A decimal is a part of a whole.

  3. 1 dollar and 4 dimes • 1.40$ Part of the whole Whole

  4. On a number line 1 4 0

  5. Converting from fraction to Decimal • THERE ARE 2 WAYS • 1) You can write the fraction with a denominator that is a power of 10. • (10,100,1000….) Denominator is the bottom number of a fraction • Ex • =

  6. Step 2 • Than move your decimal place one spot to the left, because the 10 has 1 zero. • 6. 0 .6

  7. More examples How many decimal points will I move to the left? 245.

  8. Look at money again. • It takes 10 dimes to make 1 dollar. So 1 dime is 1 tenth of the whole

  9. It takes 100 pennies to make 1 dollar A penny is one hundredth of a dollar

  10. Second way • Divide the numerator by the denominator. • 7÷16 • =0.4375

  11. Express the following mixed fraction as a decimal • 2 =2. a decimal • 2÷3 =0.66 • 2.66

  12. Homework • Pg 90#15,16,17 • Pg 91# 18,19,20

  13. Comparing decimal numbers • If 2 decimal numbers have different wholes • Ex. • 4.56 and 7.89 • The one with the larger whole is bigger.

  14. Comparing decimal numbers • If the 2 numbers have the same whole but different decimal numbers. • 6.54 and 6.43 • The one with the larger tenth digit is bigger

  15. Adding and subtracting decimals • Example : 235.7 +18.276 • 1) Write digits with the same position under each other and line up the decimal point. • 235.7 • + 18.276 • 2) Add or (subtract) the numbers ignoring the decimal point. • 235.7 • + 18.276

  16. Adding and subtracting decimals • 3) Place the decimal point directly under the decimal of the other numbers. • 2 3 5 .7 • + 1 8 .2 7 6 • 2 5 3. 976

  17. Homework Pg 94#1-5

  18. Word Problem • You are going shopping for groceries and you want to save as much money as possible. Here are the prices at 2 stores: Which Grocery store would give you the best deal overall and how much would it cost?

  19. Pg 95 • #7-11

  20. Multiplication and division of decimals • 1) When multiplying by a power of ten (10,100,1000…) Move the decimal one place to the right for every zero Example: 3.45 X100 3.45 =345.00

  21. Multplication with decimal numbers Move the decimal one place to the Left for every zero. 003.45 =.00345

  22. Multiplication • For all other numbers, • 1) Multiply them as if they were not decimal numbers. • 35.18 • X 4.7 • 24 626 • + 1 40 720 • 1 65 346 • 2) Count the number of decimal places in the 2 numbers • we have 3. • 3) Put the decimal place in the result so it is same as the total of the 2 numbers.

  23. Homework • Pg 96 • ALL • Pg 97 #3 & 4

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