Mixed Numbers & Fractions FAQs
Q: What are mixed numbers and improper fractions?
Mixed Numbers: A mixed number combines a whole number and a proper fraction (where the numerator is smaller than the denominator). It represents a value greater than 1.
Example: 2 ¾
(two and three-fourths)
Improper Fractions: An improper fraction is a fraction where the numerator (top number) is greater than or equal to the denominator (bottom number). It also represents a value greater than or equal to 1.
Example: 11/4
(eleven-fourths)
You write a mixed number as: Whole Number Numerator/Denominator.
Q: How do I convert a mixed number to an improper fraction?
To convert a mixed number to an improper fraction:
- Multiply the whole number by the denominator of the fraction.
- Add the result to the numerator of the fraction.
- Write this new sum as the numerator of the improper fraction, keeping the original denominator.
Example: Convert 3 ½
to an improper fraction.
- Multiply whole number by denominator:
3 × 2 = 6
- Add the result to the numerator:
6 + 1 = 7
- The improper fraction is
7/2
.
This process effectively counts how many "pieces" (defined by the denominator) are in the whole number part and adds them to the pieces in the fractional part.
Q: How do I convert an improper fraction to a mixed number?
To convert an improper fraction to a mixed number:
- Divide the numerator by the denominator.
- The quotient (the whole number part of the division result) becomes the whole number part of the mixed number.
- The remainder of the division becomes the numerator of the fractional part.
- The original denominator stays the same.
Example: Convert 11/4
to a mixed number.
- Divide 11 by 4:
11 ÷ 4 = 2
with a remainder of3
. - The quotient (whole number) is
2
. - The remainder (new numerator) is
3
. - The denominator stays
4
. - The mixed number is
2 ¾
.
Q: How do I multiply mixed numbers (with fractions, whole numbers, or other mixed numbers)?
The easiest way to multiply mixed numbers is to first convert them into improper fractions.
- Convert all mixed numbers (and whole numbers) to improper fractions.
- To convert a mixed number, see the FAQ above.
- To convert a whole number to an improper fraction, write the whole number over 1 (e.g.,
5
becomes5/1
). - Regular fractions are already in the correct format.
- Multiply the numerators together to get the new numerator.
- Multiply the denominators together to get the new denominator.
- Simplify the resulting fraction if possible, and convert it back to a mixed number if it's improper and the context requires it.
Example 1: Multiply 1 ½
by 2 ¾
- Convert to improper fractions:
1 ½ = 3/2
and2 ¾ = 11/4
. - Multiply numerators:
3 × 11 = 33
. - Multiply denominators:
2 × 4 = 8
. - Result:
33/8
. - Convert back to mixed number:
33 ÷ 8 = 4
with a remainder of1
. So,33/8 = 4 ⅛
.
Example 2: Multiply 2 ⅓
by ⅖
(mixed number by a fraction)
- Convert
2 ⅓
to7/3
. The fraction⅖
stays as is. - Multiply numerators:
7 × 2 = 14
. - Multiply denominators:
3 × 5 = 15
. - Result:
14/15
(already a proper fraction).
Example 3: Multiply 1 ¼
by 3
(mixed number by a whole number)
- Convert
1 ¼
to5/4
. Convert3
to3/1
. - Multiply numerators:
5 × 3 = 15
. - Multiply denominators:
4 × 1 = 4
. - Result:
15/4
. Convert to mixed number:3 ¾
.
Q: How do I divide mixed numbers (with fractions, whole numbers, or other mixed numbers)?
Similar to multiplication, first convert all mixed numbers (and whole numbers) to improper fractions.
- Convert all mixed numbers (and whole numbers) to improper fractions. (See multiplication FAQ for conversion details).
- Keep the first fraction as it is.
- Change the division sign to a multiplication sign.
- Flip (invert) the second fraction (the divisor). This is called finding the reciprocal.
- Multiply the fractions as described in the multiplication FAQ (multiply numerators, multiply denominators).
- Simplify the result and convert to a mixed number if needed.
Example: Divide 3 ½
by 1 ¾
- Convert to improper fractions:
3 ½ = 7/2
and1 ¾ = 7/4
. - The problem becomes
7/2 ÷ 7/4
. - Keep the first, change to multiply, flip the second:
7/2 × 4/7
. - Multiply numerators:
7 × 4 = 28
. - Multiply denominators:
2 × 7 = 14
. - Result:
28/14
. - Simplify:
28/14 = 2
.
This process applies when dividing a mixed number by a fraction, a mixed number by a whole number, or a whole number by a mixed number – always convert to improper fractions first.
Q: How do I add mixed numbers?
There are two common methods for adding mixed numbers:
Method 1: Add Whole Numbers and Fractions Separately
- Add the whole number parts together.
- Add the fractional parts together.
- If the fractions have different denominators, find a common denominator first.
- If the sum of the fractions is an improper fraction, convert it to a mixed number and add its whole number part to the sum of the whole numbers.
- Combine the results and simplify the final fractional part if needed.
Example: Add 2 ¼
+ 1 ½
- Add whole numbers:
2 + 1 = 3
. - Add fractions:
¼ + ½
. Find common denominator (4):¼ + 2/4 = ¾
. - Combine:
3 ¾
.
Method 2: Convert to Improper Fractions
- Convert all mixed numbers to improper fractions.
- Find a common denominator if the denominators are different.
- Add the numerators, keeping the common denominator.
- Convert the resulting improper fraction back to a mixed number and simplify.
Example: Add 2 ¼
+ 1 ½
using improper fractions
- Convert:
2 ¼ = 9/4
,1 ½ = 3/2
. - Common denominator for
9/4
and3/2
(which is6/4
) is 4. - Add:
9/4 + 6/4 = 15/4
. - Convert back:
15/4 = 3 ¾
.
This applies to adding mixed numbers with fractions (treat the fraction as having a whole part of 0) or with whole numbers (treat the whole number as having a fractional part of 0).
Q: How do I subtract mixed numbers?
Similar to addition, there are two main methods:
Method 1: Subtract Whole Numbers and Fractions Separately (with potential borrowing)
- Subtract the fractional parts.
- Find a common denominator if necessary.
- If the first fraction is smaller than the second, you'll need to "borrow" 1 from the whole number part of the first mixed number. Add this borrowed 1 (in the form of fraction, e.g.,
4/4
,5/5
) to the first fraction before subtracting.
- Subtract the whole number parts.
- Combine the results and simplify.
Example: Subtract 3 ¼
– 1 ¾
- Fractions:
¼ – ¾
. Since¼
is smaller than¾
, borrow 1 from the3
. The3
becomes2
. The borrowed1
is added to¼
as4/4
, so¼ + 4/4 = 5/4
. Now subtract fractions:5/4 – ¾ = 2/4
. - Whole numbers:
2 – 1 = 1
(remember we borrowed from the 3). - Combine:
1 2/4
. Simplify:1 ½
.
Method 2: Convert to Improper Fractions
- Convert all mixed numbers to improper fractions.
- Find a common denominator if necessary.
- Subtract the numerators, keeping the common denominator.
- Convert the result back to a mixed number and simplify if needed.
Example: Subtract 3 ¼
– 1 ¾
using improper fractions
- Convert:
3 ¼ = 13/4
,1 ¾ = 7/4
. - Subtract:
13/4 – 7/4 = 6/4
. - Convert back and simplify:
6/4 = 1 2/4 = 1 ½
.
This applies when subtracting a fraction from a mixed number, or a mixed number from a whole number (convert the whole number to a mixed number with a 0 fraction or to an improper fraction).
Q: How do I convert mixed numbers to decimals?
To convert a mixed number to a decimal:
- Keep the whole number part as it is; this will be the part of the decimal before the decimal point.
- Convert the fractional part to a decimal by dividing the numerator by the denominator.
- Combine the whole number part and the decimal part.
Example: Convert 3 ¾
to a decimal.
- The whole number part is
3
. - Convert the fraction
¾
: Divide3
by4
.3 ÷ 4 = 0.75
. - Combine: The whole number
3
plus the decimal0.75
gives3.75
.
Alternatively, convert the mixed number to an improper fraction first, then divide the numerator by the denominator. For 3 ¾ = 15/4
, then 15 ÷ 4 = 3.75
.
Q: How do I convert decimals to mixed numbers?
To convert a decimal to a mixed number (if the decimal is greater than 1):
- The whole number part of the decimal becomes the whole number part of the mixed number.
- Take the decimal part (the digits after the decimal point) and write it as the numerator of a fraction.
- The denominator of the fraction will be a power of 10 (10, 100, 1000, etc.) corresponding to the number of decimal places.
- 1 decimal place: denominator is 10.
- 2 decimal places: denominator is 100.
- 3 decimal places: denominator is 1000, and so on.
- Simplify the fractional part of the mixed number to its lowest terms.
Example: Convert 5.25
to a mixed number.
- The whole number part is
5
. - The decimal part is
.25
. Write this as25
(numerator). - There are two decimal places, so the denominator is
100
. The fraction is25/100
. - Combine:
5 25/100
. - Simplify the fraction
25/100
by dividing both numerator and denominator by their greatest common divisor (25):25÷25 / 100÷25 = 1/4
. - The mixed number is
5 ¼
.
Q: How do I simplify mixed numbers?
To simplify a mixed number, you simplify its fractional part. The whole number part remains unchanged unless the fractional part was improper and got converted, changing the whole number.
- Look at the fractional part of the mixed number.
- Find the greatest common divisor (GCD) of the numerator and the denominator.
- Divide both the numerator and the denominator by their GCD.
Example: Simplify 4 6/8
.
- The fractional part is
6/8
. - The GCD of 6 and 8 is 2.
- Divide numerator by GCD:
6 ÷ 2 = 3
. - Divide denominator by GCD:
8 ÷ 2 = 4
. - The simplified fractional part is
¾
. - The simplified mixed number is
4 ¾
.
If an operation results in a mixed number with an improper fraction (e.g., 2 5/3
), first convert the improper fraction part to a mixed number (5/3 = 1 2/3
), then add the whole parts (2 + 1 2/3 = 3 2/3
).