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Decimal Place Value:

Decimal Place Value:. Decimal points are read as the word “and” Place values to the right of the decimal point represent part of a whole Read the numbers in groups of three then read the place value name Place values to the right of the decimal point end with “ths”

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Decimal Place Value:

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  1. Decimal Place Value: • Decimal points are read as the word “and” • Place values to the right of the decimal pointrepresent part of a whole • Read the numbers in groups of three then read the place value name • Place values to the right of the decimal point end with “ths” • Place values to the right of the decimal point “mirror” place values to the left of the decimal point

  2. Decimal Place Value: ___ ___ ___ ___ ___ ___ ___ Units Thousands Hundreds Tens Tenths Hundredths Thousandths

  3. Rounding Decimals: Steps for Rounding: Step 1:Identify the place value you are rounding to and underline it Step 2:Circle the number to the right Step 3:Determine whether to “round up” or to “round down” • If the circled number is 0-4, the underlined number stays the same and all the digits to the right of the circled number fall off • If the circled number is 5-9, the underlined number goes up one and all the digits to the right of the circled number fall off

  4. Rounding Practice Problems: 4.6 4.58 13.8 13.80 179.86 179.9

  5. Comparing Decimals: • Steps for Comparing Decimals Values • Step 1: List the numbers vertically • “Stack” the decimal points • Add zeros as place holders as needed • Step 2: Compare the whole number part then • compare the decimal parts moving to the right (as you would if you were alphabetizing words) • Step 3: Put in the correct order (from least to greatest or greatest to least)

  6. Comparing Decimals Practice: Practice Problems: Arrange each group of numbers in order from least to greatest. 0.342 0.304 0.324 0.340 2.37 2.7 2.3 2.73 To Compare = Be Fair! 0.304 0.324 0.340 0.342 2.3 2.37 2.7 2.73

  7. Comparing Decimals Practice: Practice Problems: Arrange each group of numbers in order from least to greatest. 5.23 5.023 5.203 5.032 1.010 1.101 1.011 1.110 To Compare = Be Fair! 5.023 5.032 5.203 5.23 1.010 1.011 1.101 1.110

  8. Basic Operations with Decimals: • Addition and Subtraction • Step 1: Write the numbers vertically • “Stack” the decimal points • Add zeros as place holders • Step 2: Move the decimal point straight down into your answer • Step 3: Add or subtract

  9. Adding and Subtracting Decimals Practice: Practice Problems: Find the sum for each. 2.3 + 3.71 + 27 = 33.01 1 1 2.30 Be Fair! 3.71 + 27.00 3 3 .01

  10. Adding and Subtracting Decimals Practice: Practice Problems: Find the sum for each. 3.14 + 2.073 + 8.9 = 14.113 1 1 3.140 Be Fair! 2.073 + 8.900 14 .1 13

  11. Adding and Subtracting Decimals Practice: Practice Problems: Find the difference for each. 31.73 – 12.07 = 9 – 8.185 = 23.5 – 17.097 = 19.66 0.815 6.403 Be Fair!

  12. Adding and Subtracting Decimals Practice: Practice Problems: Find the sum or difference for each. 4.66 – 2.45 = 3 + 5.76 + 0.11 = 25 – 0.14 + 2.36 = 2.21 8.87 27.22 Be Fair!

  13. Multiplying Decimals: Steps for Multiplication Step 1: Write the problem vertically (just as you would a regular multiplication problem) Step 2: Ignore the decimal point(s) and multiply as if you were multiplying whole numbers Step 3: Determine where the decimal point goes in the product However many digits are to the right of the decimal point(s) in the problem… that’s how many digits are to be to the right of the decimal point in the product.

  14. Multiplying Decimals Practice: • Practice Problems: • Find the product of each. • 2 x 3.14 = 6.28 Note (2 dp) 314 x2 628

  15. Multiplying Decimals Practice: Practice Problems: Find the product of each. 8.097 x .05 = 0.40485 Note (5 dp) 8097 x5 40485

  16. Multiplying Decimals Practice: • Practice Problems: • Find the product of each. • 1.042 x 2.3 = E X T E N S I O N 2.3966 Note(4 dp) 1042 Equivalent methods are possible x23 3126 20840 23966

  17. Multiplying Decimals Practice: • Practice Problems: Find the product of each. • 4.7 x 1000 = • 3 x 0.567 = • 0.27 x 15 = E X T E N S I O N 4700 1.701 4.05

  18. Multiplying Decimals Practice: • Practice Problems: Find the product of each. • (2.5)(1.5) = • (1.3)(7) = • 5.41 x 200 = E X T E N S I O N 3.75 9.1 1082

  19. Dividing with Decimals: There are 2 types of division problems involving decimal points: No decimal in the divisor Decimal in the divisor

  20. Division with Decimals: NO decimal point in the divisor… Step 1: Write the problem in the traditional long division format Step 2: Move the decimal point in the dividend straight up into the quotient Step 3: Divide as usual Remember to divide out one more place than you are rounding to…

  21. Division with Decimals: Yes…Decimal point in the divisor… Step 1: Write the problem in the traditional long division format Step 2: Move the decimal point in the divisor to the far right of the divisor Step 3: Move the decimal point the SAME number of places in the dividend Step 4: Move the decimal point in the dividend straight up into the quotient Step 5: Divide as usual Remember to divide out one more place than you are rounding to…

  22. Division Practice: Practice Problems: Find the quotient for each. 3.753  3 = 8.7  100 = 245.9 ÷ 1000 = 0.65 ÷ 5 = 1.251 3 1.251 0.087 0.2459 0.13 3.753

  23. Division Practice: Practice Problems: Find the quotient for each. 428.6 ÷ 2 = 2.436 ÷ 0.12 = 4.563 ÷ 0.003 = 21.35 ÷ 0.7 = 2 E X T E N S I O N 428.6 214.3 20.3 1521 30.5 12 243.6 3 4563 7 213.5

  24. Division Practice: Practice Problems: Find the quotient for each. 97.31 ÷ 5 = 0.8542 ÷ 0.2 = 67.337 ÷ 0.02 = 1500.4 ÷ 1000 = E X T E N S I O N 19.462 4.271 3369.5 1.5004

  25. Problem Solving with Decimals: Follow the correct Order of Operations only remember to apply the rules that go with decimals. B.O.D.M.A.S. B– Brackets O – Of D- Division M – Multiplication A – Addition S – Subtraction Do whichever one comes first working from left to right

  26. Order of Operations Practice: Practice Problems: Solve each by following the correct order of operations. 2.3 x 4  2 + 4 = 3.5  7 + 2.15 x 0.13 = 2(7 – 2.49) + 0.3 = 14  0.2 + (3.1 – 2.56) x 2 = E X T E N S I O N 8.6 0.7795 9.32 71.08

  27. Order of Operations Practice: Practice Problems: Solve each by following the correct order of operations. 5 + (7.8 – 5.5)2 – 9.3 = (40 ÷ 0.5 x 7) + 5 – 14 = -8 x 0.75 + 15.23 – 4 = E X T E N S I O N 0.99 551 5.23

  28. FINALLY GOOD LUCK in YOUR TEST

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