Standard Form And Decimal Numbers In Standard Form Archives

Difference between Whole Numbers and Decimal Numbers Whole number is a number without fraction. For example 1, 2, 3, 41000, 38888 are examples of whole numbers.71/2 is not a whole number. A decimal number is a fractional number less than 1. It is smaller to a whole number. Examples - 0.1,0.01,0.001etc Whole Numbers in Standard Form and Decimal Numbers in Standard Form Whole numbers in standard form are expressed in the form of A x 10n such that A is a number between 1 and 10, n is a whole number. Example Express the following in standard form (a) 200 (b) 4100 (c) 300000 Solution 200 2 x 100 2x102 4100 4.1 x 1000 4.1 x 103 300000 3 x 100000 3 x 105 Evaluation Express the following in standard form (a) 500 (b) 36000 (c) 7200000 Decimal fractions such as 0.00 and 0.000001 can be expressed as powers of 10 e.g. 0.0001 1/10000 1/104 10-4 Thus, any decimal fraction can be expressed in a standard form e.g. 0.0088/10008/103 8x1/1038x10-3 Therefore, the number 8x10-3 is in standard form ax10 and n is a negative integer while A is a number between1 and 10 Example Express the following in standard form (a) 0.0023 (b) 0.00034 (c) 0.125 Solution 023 23/1000 2.3/102 2.3 x 10-3 00034 34/100000 3.4/104 3.4x 10-4 125 125/1000 1.25/101 1.25x10-1 Evaluation Express the following in standard form (a) 0.0067 (b) 0.00082 (c) 0.012 FACTORS, MULTIPLES AND PRIME NUMBERS The factors of a number are the whole numbers that divide the number exactly. For example the factors of 10 are 1, 2 and 5. A prime number has only two factors, itself and 1. The following are examples of prime numbers 2, 3, 5, 7, 11,13. However, 1 is not a prime number. A multiple of a whole number is obtained by multiplying it by any whole number. Example Write down all the factors of 18. State which of theses factors are prime numbers Write the first three multiples of 18 Express 18 as a product of its prime factors in index form Solution: Factors of 18:1, 2,3,6,9 and 18. Prime numbers of the factors of 18:2 and3 The first three multiples of 18 are 1x18 18, 2x1836, 3x1854 > 18, 36 and 54. 18 2x3x3 2 x 32 in index form Example 2: Write down all the factors of 22. State which of theses factors are prime numbers Write the first three multiples of 22 Solution: Factors of 22:1, 2, and 11. Prime numbers of the factors of 22: 2 and11 The first three multiples of 22 are 1x22 22, 2x2244, 3x2266 > 22, 44 and 66. Evaluation Write down all the factors State which of theses factors are prime numbers Write the first three multiples of each of the following numbers below Express each as a product of its prime factors in index form 12 (2) 30 (3) 39 (4) 48 WEEKEND ASSIGNMENT Which of these is not a prime number (a) 2 (b) 5 (c) 7 ( d) 1 Express 360000 in standard form (a) 3.6 x 105 (b) 3.6 x 106 (c) 3.6 x 103 ( d) 3.6 x 104 Express 0.000045 in standard form (a) 4.5 x 10-2 (b) 4.5 x 103 (c) 4.5 x 10-5 (d) 4.5 x 10-6 Which of these is not a factor of 42 (a) 9 (b) 6 (c) 7 (d) 2 Express 50 is product of its prime factor (a) 2 x 52 (b) 2 x 5 (c) 22 x 52 (d) 2 x 5 THEORY For each number 42,45,48,50 Write down all its factors. State which factors are prime numbers? Express the number as a product of its prime factors. Express the following in standard form (a) 345000 (b) 0.00034 (c) 0.125 See also BASIC OPERATION OF INTEGERS WEIGHT VOLUME OF CYLINDER AREA OF RIGHT ANGLED TRIANGLE PROFIT AND LOSS PERCENT

WHOLE NUMBERS AND DECIMAL NUMBERS