29/31 - 67/28 = ? Subtracting ordinary (common) fractions, online calculator, subtraction operation explained step by step. The answer, written in four ways. As a negative improper fraction (the numerator >= the denominator). As a mixed number. As a decimal number. As a percentage.
29/31 - 67/28 = ?
Simplify the operation
Reduce (simplify) the fractions to their lowest terms equivalents:
To fully reduce a fraction, to the lowest terms equivalent: divide the numerator and denominator by their greatest common factor, GCF.
* Why do we try to reduce (simplify) the fractions?
By reducing the values of the numerators and the denominators of the fractions the calculations are easier to make.
A fully reduced (simplified) fraction is one with the smallest possible numerator and denominator, one that can no longer be reduced, and it is called an irreducible fraction.
* * *
The fraction: 29/31 is already reduced to the lowest terms. The numerator and denominator have no common prime factors. Their prime factorization: 29 is a prime number 31 is a prime number GCF (29; 31) = 1
The fraction: - 67/28 is already reduced to the lowest terms. The numerator and denominator have no common prime factors. Their prime factorization: 67 is a prime number 28 = 22 × 7 GCF (67; 22 × 7) = 1
An improper fraction: the value of the numerator is larger than or equal to the value of the denominator.
A proper fraction: the value of the numerator is smaller than the value of the denominator.
Each improper fraction will be rewritten as a whole number and a proper fraction, both having the same sign: divide the numerator by the denominator and write down the quotient and the remainder of the division, as shown below.
Why do we rewrite the improper fractions?
By reducing the value of the numerator of a fraction the calculations are getting easier to perform.
Perform the operation of calculating the fractions.
To add or subtract fractions we need them to have equal denominators (the same common denominator).
To calculate the fractions' operation we have to:
1) find their common denominator
2) then calculate the expanding number of each fraction
3) then build up their denominators the same by expanding the fractions to equivalent forms, which all have equal denominators (the same denominator)
* The common denominator is nothing else than the least common multiple (LCM) of the denominators of the fractions.
The LCM will be the common denominator of the fractions that we work with.
1) Find the common denominator Calculate the LCM of the denominators:
The prime factorization of the denominators:
31 is a prime number
28 = 22 × 7
Multiply all the unique prime factors: if there are repeating prime factors we only take them once, and only the ones having the highest exponent (the highest powers).
2) Calculate the expanding number of each fraction:
Divide the LCM by the denominator of each fraction.
29/31: 868 ÷ 31 = (22 × 7 × 31) ÷ 31 = 28
- 11/28: 868 ÷ 28 = (22 × 7 × 31) ÷ (22 × 7) = 31
3) Build up the fractions to the same common denominator:
Expand each fraction: multiply both its numerator and denominator by its corresponding expanding number, calculated at the step 2, above. This way all the fractions will have the same denominator.
Then keep the common denominator and work only with the numerators of the fractions.
- 2 + 29/31 - 11/28 =
- 2 + (28 × 29)/(28 × 31) - (31 × 11)/(31 × 28) =
- 2 + 812/868 - 341/868 =
- 2 + (812 - 341)/868 =
- 2 + 471/868
Fully reduce (simplify) the fraction to its lowest terms equivalent:
To fully reduce a fraction, to the lowest terms equivalent: divide the numerator and denominator by their greatest common factor, GCF.
A fully reduced (simplified) fraction is one with the smallest possible numerator and denominator, one that can no longer be reduced, and it is called an irreducible fraction.
471/868 is already reduced to the lowest terms.
The numerator and denominator have no common prime factors.
As a negative improper fraction: (the numerator >= the denominator)
An improper fraction: the value of the numerator is larger than or equal to the value of the denominator.
- 2 + 471/868 =
( - 2 × 868)/868 + 471/868 =
( - 2 × 868 + 471)/868 =
- 1,265/868
As a mixed number (also called a mixed fraction):
A mixed number: a whole number and a proper fraction, both having the same sign.
A proper fraction: the value of the numerator is smaller than the value of the denominator.
Divide the numerator by the denominator and write down the quotient and the remainder of the division, as shown below:
- 1,265 ÷ 868 = - 1 and the remainder = - 397 =>
- 1,265 = - 1 × 868 - 397 =>
- 1,265/868 =
( - 1 × 868 - 397)/868 =
( - 1 × 868)/868 - 397/868 =
- 1 - 397/868 =
- 1 397/868
As a decimal number:
Simply divide the numerator by the denominator, without a remainder, as shown below:
- 1 - 397/868 =
- 1 - 397 ÷ 868 ≈
- 1.457373271889 ≈
- 1.46
As a percentage:
A percentage value p% is equal to the fraction: p/100, for any decimal number p. So, we need to change the form of the number calculated above, to show a denominator of 100.
To do that, multiply the number by the fraction 100/100.
The value of the fraction 100/100 = 1, so by multiplying the number by this fraction the result is not changing, only the form.
As a negative improper fraction: (the numerator >= the denominator) 29/31 - 67/28 = - 1,265/868
As a mixed number (also called a mixed fraction): 29/31 - 67/28 = - 1 397/868
As a decimal number: 29/31 - 67/28 ≈ - 1.46
As a percentage: 29/31 - 67/28 ≈ - 145.74%
How are the numbers being written on our website: comma ',' is used as a thousands separator; point '.' used as a decimal separator; numbers rounded off to max. 12 decimals (if the case). The set of the used symbols on our website: '/' the fraction bar; ÷ dividing; × multiplying; + plus (adding); - minus (subtracting); = equal; ≈ approximately equal.
Fractions subtractions: the latest fractions subtracted by the users
The expanding number is the non-zero number that will be used to multiply both the numerator and the denominator of each fraction, in order to build all the fractions up to the same common denominator.
Divide the least common multiple, LCM, calculated above, by the denominator of each fraction, in order to calculate each fraction\'s expanding number.
4. Expand each fraction:
Multiply each fraction\'s both numerator and denominator by the expanding number.
At this point, fractions are built up to the same denominator.
5. Subtract the fractions:
In order to subtract all the fractions simply subtract all the fractions\' numerators.
The end fraction will have as a denominator the least common multiple, LCM, calculated above.
6. Reduce the end fraction to the lowest terms, if needed.