explain how to add and subtract fractions with unlike denominators?
21544
['Find the smallest multiple (LCM) of both numbers.', 'Rewrite the fractions as equivalent fractions with the LCM as the denominator.']
23725
If the two rational expressions that you want to add or subtract have the same denominator you just add/subtract the numerators which each other. When the denominators are not the same in all expressions that you want to add or subtract as in the example below you have to find a common denominator.
183718
Write both fractions as equivalent fractions with a denominator of 15. Since you're trying to subtract a larger fraction from a smaller one, you need to "borrow" a one from the integer 4, change it to 15/15, and add it to the fraction. Now the problem becomes 3 20/15 minus 3 9/15 and the answer is 11/15.
1160084
Subtraction of Algebraic Fractions. To subtract algebraic fractions, first express them in terms of their Lowest Common Denominator (LCD) and then subtract their numerators to obtain the numerator that is divided by the LCD to arrive at the answer.
748936
Student response: addition. "We will add the fractions." I explain to the students that in order to add fractions with like denominators, all we have to do is add the numerator, which is the top number. If you are subtracting fractions with like denominators, you just subtract the top numbers.
131180
Fractions - Adding and Subtracting fractions - First Glance. Like fractions are fractions with the same denominator. You can add and subtract like fractions easily - simply add or subtract the numerators and write the sum over the common denominator.
858114
Subtracting fractions from whole numbers isn't as hard as it looks. There are two main ways to go about it: you can either convert the whole number into a fraction, or subtract 1 from that whole number and convert the 1 into a fraction with the same base as the fraction you're subtracting from it.
1396675
['Things to remember:', 'Step 1: Find a common multiple of the denominators.', 'HINT: The easiest way to do this is multiply the denominators together.', 'Step 2: Multiply the fractions so that the denominators the same.', 'Step 3: Add or subtract the new fractions.', 'Step 4: See if you can simplify.']
1087280
If the fraction parts of a mixed number have the same denominator and if we are subtracting a smaller fraction from a larger fraction, then the subtraction is straightforward: subtract the fractions and then subtract the whole numbers.
229836
['To add or subtract rational expressions with unlike denominators, first find the LCM of the denominator. ... ', 'Write each expression using the LCD. ... ', 'Add or subtract the numerators.', 'Simplify as needed.']
39071
['Find a common denominator by multiplying the two denominators together.', 'Manipulate the fractions so that they both have the common denominator.', 'Once you have a common denominator in both fractions, subtract the numerators.']
407776
['Find the least common denominator.', 'Change each fraction to an equivalent fraction having the LCD as its denominator.', 'Add the numerators and place over the LCD.', 'Simplify or reduce the answer.']
1101755
["Multiply the whole number part by the fraction's denominator.", 'Add that to the numerator.', 'Then write the result on top of the denominator.']
1392795
['Things to remember:', 'Step 1: Find a common multiple of the denominators.', 'HINT: The easiest way to do this is multiply the denominators together.', 'Step 2: Multiply the fractions so that the denominators the same.']
236
['Find the least common denominator.', 'Make equivalent fractions using the LCD.', 'Add or subtract the numerators.', 'Simplify the result if necessary.']
1134512
Subtracting mixed numbers works much the same way as adding mixed numbers. To subtract mixed numbers, subtract the whole number parts of the mixed numbers and then subtract the fraction parts in the mixed numbers. Finally, combine the whole number answer and the fraction answer to express the answer as a mixed number.
1189933
['Put the numbers in a vertical column aligning the decimal points.', 'Subtract each column, starting on the right and working left. ... ', 'Place the decimal point in the answer directly below the decimal points in the terms.', 'Check the answer by adding.']