CD3 M31 - August 21, 2017
LESSON 1
Estimation in Everyday Life
To estimate means "to judge tentatively or approximately the value, worth or significance of something"
Decimals are real numbers expressed in base 10
Whole numbers are nonnegative integers
The numerator is the number above the line in a fraction while the number below the line is called the denominator
In order to make an accurate estimate, it is necessary to round off the given number/s to the nearest whole number/s
In rounding off mixed numbers, we follow these steps
Convert the fraction part into decimal form
Write the decimal form of the mixed number
Look at the digit written right after the decimal point
- If the digit is less than 5, drop the number to the right of the decimal point and retain the whole number
- If the digit is equal to 5 or more, drop the numbers to the right of the decimal point and round off th whole number to the next higher number
Whole numbers can be rounded off to the nearest tens, hundreds, thousands, ten thousands, etc. Similarly decimals can be rounded off to the nearest tenths, hundredths, thousandths, ten thousandths, etc.
To round off a number to the nearest indicated place value, remember the following:
- If the digits to be dropped from a number is less than one-half of the number representing the indicated place value (e.g. 450 in 1450 to be rounded off to the nearest thousands), just drop the numbers after the said place value (450) and replace them with zeros (000) retaining the number immediately to their left ( 1, thereby making the answer to the given example 1000, as in 1450 rounded off to the nearest thousands is equal to 1000)
- If the digit is to be dropped from a number is exactly one-half or more of the number representing the indicated place value (e.g., 580 in 2580 to be rounded off to the nearest hundreds), drop the numbers after the said place value (580) and replace them with zeros (000) adding 1 to the value of the number immediately to their left ( 2 + 1 = 3, thereby making the answer to the given example 3000, as in 2580 rounded off to the nearest thousands is equal to 3000)
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LESSON 2
Estimating Quantities
Knowledge about estimation is important in our daily lives especially when dealing with our business or sources of livelihood
In order to make an accurate estimate of the value of goods or profit, round them off to the nearest multiple of 5, for example, for easier computation
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