what is the total thickness in inches of the tabletop

Question

Craig  glued  a piece  of oak that is 5/16 inch  thick to a piece  of pine that is 7/8 inch thick. What is the total  thickness  in inches of the tabletop 

Answer 1

To add fractions, you first need to change the fractions into equivalent fractions that have a common denominator (the same number on the bottom.)

 

So you need to find a number that is a multiple of both 16 and 8 (the two denominators.)  It's a good idea to first always check if you can use one of the denominators you already have.  In this case, we can use 16 since it is a multiple of both 16 and 8:

 

1 x 16 = 16

2 x  8  = 16

 

So lets convert 7/8 to an equivalent fraction with a denominator of 16:

 

 7              7 x 2           14

---     =   -----------   =   -----    

 8              8 x 2           16

 

Now let's add the two fractions:

 

  5           14         19            (find the sum of the numerators)

 ----    +   ----    =  -----

 16           16        16             (the denominator stays the same)

 

Since our sum is an improper fraction (numerator > denominator) we should simplify it by changing it into a mixed number.  Do you know how to do that?

 

19/16 = 1 r3

 

so our answer is 1 3/16 inches think