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Unit 1. The Number System for grade 5.pptx
- 1. Unit 1 :THENUMBER SYSTEM
- 2. 1.1 Understanding PlaceValue Place value is a fundamental concept in mathematics that helps us understand the value of each digit in a number. It is based on the idea that the position of a digit determines its value. Whole Numbers Whole numbers are numbers without any fractional parts. They are represented by digits placed in specific positions, each representing a power of ten. e.g : 708, 1906, 35612, etc Decimal Numbers Decimal numbers are numbers that include a decimal point, representing fractional parts. The digits after the decimal point also have specific positions with corresponding powers of ten. e.g : 0.8 , 1.98 , 2.056, etc.
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- 5. Multiplying and DividingWhole Numbers by 10, 100, and 1000 1 Multiplying by 10 To multiply a whole number by 10, simply add a zero to the right of the number. For example, 5 x 10 = 50. 2 Dividing by 10 Dividing a whole number by 10 is the opposite of multiplying by 10. Remove the last digit to divide by 10. For example, 50 / 10 = 5. 3 Multiplying by 100 Multiplying a whole number by 100 is like adding two zeros. 5 x 100 = 500. 4 Dividing by 100 Dividing a whole number by 100 is like removing the last two digits. 500 / 100 = 5. 5 Multiplying by 1000 To multiply by 1000, add three zeros to the right. 5 x 1000 = 5000. 6 Dividing by 1000 Dividing by 1000 is like removing the last three digits. 5000 / 1000 = 5.
- 6. Multiplying and DividingDecimal Numbers by 10, 100, and 1000 1 Multiplying by 10 To multiply a decimal number by 10, simply move decimal point one step to the right. e.g : 7.4 x 10 = 74 , 0.89 x 10 = 8.9 2 Dividing by 10 Dividing a decimal number by 10 is the opposite of multiplying by 10. Move decimal point one step to the left. e.g : 1.2 á 10 = 0.12 , 71.35 á 10 = 7.135 3 Multiplying by 100 4 Dividing by 100 5 Multiplying by 1000 6 Dividing by 1000 Dividing a decimal number by 100, is the opposite of multiplying by 10. Move decimal point two steps to the left. e.g : 17.4 á 100 = 0.174 , 38 á 100 = 0.38 To multiply a decimal number by 1000, simply move decimal point three steps to the right. e.g : 7.4 x 1000 = 7400 , 0.89 x 1000 = 890 Dividing a decimal number by 1000 is the opposite of multiplying by 1000. Move decimal point three steps to the left. e.g : 12.2 á 1000 = 0.012 , 71.35 á 1000 =0.07135 To multiply a decimal number by 100, simply move decimal point two steps to the right. e.g : 7.4 x 100 = 740 , 0.89 x 100 = 89
- 7. Ten thousands Thousands Hundreds TensOnes Tenths Hundredths Thousandths . . Place Value Chart Whole numbers Decimal numbers X 10 : 10 X 100 X 1000 : 100 : 1000 Move decimal point one step to the right Move decimal point two steps to the right Move decimal point three steps to the right Move decimal point one step to the left Move decimal point two steps to the left Move decimal point three steps to the left
- 8. Multiply and DivideDecimal Numbers with 10, 100, and 1000
- 9. Letâs Discuss! 40.7 x10 = ⌠2100 : 100 = ⌠650 : 1000 = ⌠345 : 100 = ⌠512 : 100 = ⌠21.52 x 10 = ⌠8.34 x 10 = ⌠4.316 : 100 = ⌠53.81 x 1000 = âŚ
- 12. 1.2 Rounding decimalnumbers Rounding decimal numbers is the act of reducing or increasing an amount (number) to the nearest whole number, tenth, hundredth, and thousandth
- 13. Rounding â tothe nearest whole number (check tenth) 4.5 yes 5 or more? 5 12.37 No 5 or more? 12 8.71 yes 5 or more? 9
- 14. Round these numberto the nearest numbers whole number! 3.9 = ⌠7.28 = ⌠21.56 = ⌠41.325 = ⌠831.5 = ⌠10.27 = âŚ
- 15. Rounding â tothe nearest tenth (check hundredth) 4.53 no 5 or more? 4.5 12.37 yes 5 or more? 12.4 8.713 no 5 or more? 8.7
- 16. Round these numbersto the nearest tenth! 5.47 = ⌠6.281 = ⌠31.92 = ⌠15.445 = ⌠8.375 = ⌠10.274 = âŚ
- 17. Rounding â tothe nearest hundredth (check thousandth) 4.539 yes 5 or more? 4.54 12.375 yes 5 or more? 12.38 8.713 no 5 or more? 8.71
- 18. Round these numbersto the nearest hundredth! 2.394 = ⌠6.128 = ⌠21.568 = ⌠41.374 = ⌠8.555 = ⌠10.279 = âŚ
- 19. Rounding â tothe nearest thousandth (check ten thousandth) 4.5392 no 5 or more? 4.539 12.3754 np 5 or more? 12.375 8.7136 yes 5 or more? 8.714
- 20. Round these numbersto the nearest thousandth! 1.4563 = ⌠87.3756 = ⌠5.5128 = ⌠17.3245 = ⌠31.5764 = ⌠10.2782 = âŚ