Solution - Adding, subtracting and finding the least common multiple

Reformatting the input :

Changes made to your input should not affect the solution:

(1): "0.9" was replaced by "(9/10)". 2 more similar replacement(s)

Step  1  :

             9
 Simplify   ——
            10

Equation at the end of step  1  :

   21                  9
  (—— +  -3) -  (0 -  ——)
   10                 10

Step  2  :

            21
 Simplify   ——
            10

Equation at the end of step  2  :

   21           -9
  (—— +  -3) -  ——
   10           10

Step  3  :

Rewriting the whole as an Equivalent Fraction :

 3.1   Adding a whole to a fraction

Rewrite the whole as a fraction using  10  as the denominator :

          -3     -3 • 10
    -3 =  ——  =  ———————
          1        10   

Equivalent fraction : The fraction thus generated looks different but has the same value as the whole

Common denominator : The equivalent fraction and the other fraction involved in the calculation share the same denominator

Adding fractions that have a common denominator :

 3.2       Adding up the two equivalent fractions
Add the two equivalent fractions which now have a common denominator

Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:

 21 + -3 • 10     -9
 ————————————  =  ——
      10          10

Equation at the end of step  3  :

  -9    -9
  —— -  ——
  10    10

Step  4  :

Adding fractions which have a common denominator :

 4.1       Adding fractions which have a common denominator
Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:

 -9 - (-9)      0
 —————————  =  ——
    10         10

Final result :

  0