Math Made Easy: Decimal Division
Thursday, July 16th, 2009
Division with decimals is tricky because not only do you have to put the decimal in the right place in your answer, but often you have to move around decimals before you can even solve the division problem. In this lesson, I show how to make this tricky process a bit easier.
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Duration : 0:6:3
Access full lesson containing this video at: http://www.yourteacher.com/prealgebra/decimalwordproblems.php Students learn to solve word problems that involve adding or subtracting decimals. For example: Margaret is mailing three letters that weigh 3.7 oz., 2.913 oz., and 2.82 oz. What is the combined weight of the letters?
This video contains a number of examples of converting fractions into decimals and percents.
Access full lesson containing this video at: http://www.yourteacher.com/prealgebra/multiplyingdecimals.php Students learn to multiply decimals in the same way that one would multiply whole numbers (vertically). However, at the end of the problem, students must determine where the decimal goes in the answer by counting the total number of digits to the right of the decimal point in the original numbers, then placing the decimal point in the answer so that the answer has this same total number of digits to the right of the decimal point. For example, after multiplying 1.05 x 7.4, since there are a total of 3 digits to the right of the decimal point in the original numbers, place the decimal point in the answer so that there are 3 digits to the right of the decimal point.
This video walks through the process for converting decimals into both fractions and percents.
Access full lesson containing this video at: http://www.yourteacher.com/prealgebra/subtractingdecimals.php Students learn to subtract decimals by first lining up the decimal points, then subtracting the numbers by column. For example, to subtract 9.514 — 1.6, first line up the decimal points, then subtract the digits the thousandths column, to get 4 - 0, or 4, then subtract the digits in the hundredths column, to get 1 — 0, or 1, then subtract the digits in units column, by borrowing a 1 from the 9 in the units column (which leaves an 8 in the units column), to get 15 — 6, or 9, then subtract the digits in the units column, to get 8 — 1, or 7. So 9.514 — 1.6 = 7.914.
The Rappin’ Mathematician raps about adding and subtracting decimals. For more info, visit www.MathRaps.com
Access full lesson containing this video at: http://www.yourteacher.com/prealgebra/fractiontodecimal.php Students learn to convert fractions to decimals. For example, to convert the fraction 7/10 to a decimal, first read the fraction as “7 tenths”. Next, since the tenths place is one place to the right of the decimal point, 7 tenths can be written as the decimal 0.7. To convert 11/20 to a decimal, first find a fraction that is equivalent to 11/20 that has a denominator of 100, so multiply both the numerator and denominator by 5, to get 55/100. Next, read the fraction as “55 hundredths”, which can be written as 0.55.
How to change fraction numbers to decimal numbers, then to percent numbers.
Access full lesson containing this video at: http://www.yourteacher.com/prealgebra/convertdecimaltofraction.php Students use the place value chart to convert decimals to fractions or mixed numbers. The given decimals are taken to the tenths, hundredths, thousandths, or ten-thousandths places, and the resulting fractions or mixed numbers must sometimes be reduced to lowest terms. For example, the decimal 0.4 means 4 tenths, or 4/10, which reduces to 2/5.