 # © 2007 M. Tallman 4 × 0.3= 1.2 3 × 0.25= 0.75 2.5 × 4 Step 1: Line up the lowest places (not the decimals). Step 2: Multiply as usual. Step 3: Add.

## Presentation on theme: "© 2007 M. Tallman 4 × 0.3= 1.2 3 × 0.25= 0.75 2.5 × 4 Step 1: Line up the lowest places (not the decimals). Step 2: Multiply as usual. Step 3: Add."— Presentation transcript:

4 × 0.3= 1.2

3 × 0.25= 0.75

2.5 × 4 Step 1: Line up the lowest places (not the decimals). Step 2: Multiply as usual. Step 3: Add the number of decimal places in both factors. 2.54 4 5 × Step 4: The product must have the same number of decimal places.. 2 0 01 2 1 Decimal Place 0 Decimal Place 1 + 0 = 1. 4 x 5 = 20 4 x 2 = 8 8 + 2 = 10

© 2007 M. Tallman Step 1: Line up the lowest places (not the decimals). 6 14 91 323 6 6. 32.36 × 6 Step 2: Multiply as usual. Step 3: Add the number of decimal places in both factors. 32.366 Step 4: The product must have the same number of decimal places. × 3 2 1 2 Decimal Places 0 Decimal Place 2 + 0 = 2. 6 x 6 = 36 6 x 3 = 18 18 + 3 = 21 6 x 2 = 12 12 + 2 = 14 6 x 3 = 18 18 + 1 = 19

10 = 10 × 10 × 10 × 10 × 10 = 5 10 = 10 × 10 × 10 × 10 = 4 10 = 10 × 10 × 10 = 3 10 = 10 × 10= 2 10 = 1 = 0 10 = 1 Power of ten- a number that can be written as 10 raised to some exponent. 100,000 10,000 1,000 100 10 1

© 2007 M. Tallman 1,000 × 12.5 = 12,500. 1 × 12.5 = 12.5 10 × 12.5 = 125. 100 × 12.5 = 1,250. What pattern do you notice? 10,000 × 12.5 = 125,000.

© 2007 M. Tallman 10,000 × 0.0007 = 7. 1 × 0.0007 = 0.0007 10 × 0.0007 = 0.007 100 × 0.0007 = 0.07 1,000 × 0.0007 = 0.7

ThousandsHundredsTensOnesTenthsHundredthsThousandths0 9 × 10 = 90 200 × 10 = 2,000 80 × 10 = 800 289 × 10 = 2,890 289 × 10 Multiplying by 10 means every digit must move left by 1 place 289 Fill in the empty space in the ones place with a zero.

© 2007 M. Tallman.4 × 100 = 40 7 × 100 = 700 50 × 100 = 5,000.03 × 100 = 3 57.43 × 100 = 5,743 ThousandsHundredsTensOnesTenthsHundredthsThousandths 57.43 × 100 Multiplying by 100 means every digit must move left by 2 places 574 3

© 2007 M. Tallman.6 × 100 = 60 2 × 100 = 200 30 × 100 = 3,000 32.607 × 100 = 3,260.7.00 × 100 = 0.007 × 100 =.7 ThousandsHundredsTensOnesTenthsHundredthsThousandths 32.607 × 100 Multiplying by 100 means every digit must move left by 2 places 32607

© 2007 M. Tallman.5 × 1,000 = 500 8 × 1,000 = 8,000 8.546 × 1,000 = 8,546.04 × 1,000 = 40.006 × 1,000 = 6 ThousandsHundredsTensOnesTenthsHundredthsThousandths 8.546 × 1,000 Multiplying by 1,000 means every digit must move left by 3 places 8546

© 2007 M. Tallman 0.007 × 1,000 = 7.007 × 1,000 = 7 ThousandsHundredsTensOnesTenthsHundredthsThousandths 0.007 × 1,000 Multiplying by 1,000 means every digit must move left by 3 places 7

© 2007 M. Tallman 8 × 100 = 80030 × 100 = 3,000 38 × 100 = 3,800 ThousandsHundredsTensOnesTenthsHundredthsThousandths 38 × 100 Multiplying by 100 means every digit must move left by 2 places 38 Fill in the empty space in the ones place with a zero. 00

© 2007 M. Tallman 0.2 × 100 = 205 × 100 = 500 5.2 × 100 = 520 ThousandsHundredsTensOnesTenthsHundredthsThousandths 5.2 × 100 Multiplying by 100 means every digit must move left by 2 places 52 0 Fill in the empty space in the ones place with a zero.

© 2007 M. Tallman 0.05 × 100 = 50.9 × 100 = 90 0.95 × 100 = 95 ThousandsHundredsTensOnesTenthsHundredthsThousandths 0.95 × 100 Multiplying by 100 means every digit must move left by 2 places 95

© 2007 M. Tallman 1. 10 × 19 = 2. 652 × 10 = 3. 10,000 × 8.2 = 4. 32.6 × 10 = 5. 100 × 135.9 = 190 6,520 82,000 326 13,590

© 2007 M. Tallman 6. 91.671 × 10 = 7. 10 × 1,664.9 = 8. 54 × 1,000 = 9. 1,000 × 6.5 = 10. 1234.567 × 100 = 123,456.7 6,500 916.71 16,649 54,000

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