How do you evaluate 8\frac{1}{2}-5\frac{3}{10}?

2 Answers
Oct 5, 2017

3.2 or 3 1/5

Explanation:

First, I would normally change mixed numbers to improper fractions:

8 1/2-5 3/10 to 17/2-53/10

Now we find the LCD for these two fractions. The LCD (least common denominator) would be 10

So we would adjust the fraction 17/2 to match the denominator with 10:

(17*5)/10-53/10

As the denominators are equal, we can combine the fractions.
(5*17-53)/10->

(85-53)/10->

32/10->

3 2/10 or 3.2 as a decimal or 3 1/10 (simplified)

Oct 5, 2017

3 1/5

Explanation:

"note that "8 1/2 =8+1/2

"and "5 3/10=5+3/10

"we can express the calculation in terms of whole"
"numbers and fractions"

rArr8 1/2-5 3/10

=8+1/2-(5+3/10)

=8+1/2-5-3/10

=(8-5)+1/2-3/10

=3+5/10-3/10larrcolor(blue)" common denominator of 10"

=3+2/10

=3+cancel(2)^1/cancel(10)^5

=3+1/5=3 1/5