how to add and subtract fractions ks3?
43049
Remember, you can only add and subtract fractions when the bottom numbers, or denominators, are the same. So, to add or subtract fractions: Change the fractions so they have the same denominator. Add or subtract the top numbers, or numerators.
941560
['input fractions, mixed numbers or whole numbers;', 'select. "+" - for addition fractions, "-" - for subtraction fractions, "×" - for multiplication fractions, "÷" - for division fractions;', 'press button ( "=" ).']
979469
To find the difference of two fractions with different denominators, rewrite the fractions with a common denominator before subtracting. Here is a subtraction problem. The fractions in this problem have different denominators, 8 and 4. Rewrite the fractions so they share a common denominator.
1341649
['Check to see if the fractions have the same denominator.', "If they don't have the same denominator, then convert them to equivalent fractions with the same denominator.", 'Once they have the same denominator, add or subtract the numbers in the numerator.', 'Write your answer with the new numerator over the denominator.']
149458
['Find the Least Common Multiple of the denominators (which is called the Least Common Denominator).', 'Change each fraction (using equivalent fractions) to make their denominators the same as the least common denominator.', 'Then add (or subtract) the fractions, as we wish!']
185620
['Cross-multiply the two fractions and subtract the second number from the first to get the numerator of the answer. ... ', 'Multiply the two denominators together to get the denominator of the answer. ... ', 'Putting the numerator over the denominator gives you your answer.']
1318456
['Rewrite the equation as in "Keep, Change, Flip"', 'Keep the first fraction.', 'Change the division sign to multiplication.', 'Flip the second fraction by switching the top and bottom numbers.', 'Multiply all numerators together.', 'Multiply all denominators together.', 'Reduce the result to lowest terms.']
1209033
Step 1: Separate the whole number from the fractions. Step 2: Now we will add the whole numbers together and add the fractions together. To add the fractions we need common denominators. Now that we have common denominators, we can add the numerators and leave the denominator the same.
27238
['Find the Least Common Denominator (LCD)', 'Find the equivalent fractions.', 'Add or subtract the fractions and add or subtract the whole numbers.', 'Write your answer in lowest terms.']
587065
To do this, you need to find the least common multiple (LCM) of the two denominators. To subtract fractions with unlike denominators, rename the fractions with a common denominator. Then subtract and simplify.
332696
['Step 1: Write down the decimal divided by 1, like this: decimal 1.', 'Step 2: Multiply both top and bottom by 10 for every number after the decimal point. ... ', 'Step 3: Simplify (or reduce) the fraction.']
1320670
['Fractions with the same denominators can be added (or subtracted) by adding (or subtracting) the numerators .', 'If two fractions do not have the same denominator, then find a common denominator by making equivalent fractions .', 'This is the final answer as the fraction cannot be simplified .']
21544
['Find the smallest multiple (LCM) of both numbers.', 'Rewrite the fractions as equivalent fractions with the LCM as the denominator.']
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.']
353486
['The bottom numbers (the denominators) are already the same. Go straight to step 2.', 'Add the top numbers and put the answer over the same denominator:', 'Simplify the fraction:', 'Step 1: The bottom numbers are different. ... ', 'Step 2: Add the top numbers and put them over the same denominator:', 'Step 3: Simplify the fraction:']
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.
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.']