How do you evaluate 104 - 6c + 3 for c = 1 1/2?

Jun 29, 2015

If the intended value of $c$ is $1 \frac{1}{2}$, then we get $98$. (And perhaps a lesson in why mixed number format is not good for writing on a single line.)

Explanation:

$104 - 6 c + 3$ for $c = 1 \frac{1}{2}$

Substitute:

$104 - 6 \left(1 \frac{1}{2}\right) + 3$.

Now evaluate. Remember the order of operations, we need to multiply $6 \times 1 \frac{1}{2} = 6 \times \frac{3}{2} = \frac{6}{1} \times \frac{3}{2} = \frac{3 \cdot \cancel{2}}{1} \times \frac{3}{\cancel{2}} = 9$

Now evaluate:

$104 - 9 + 3$ by doing Addition and Subtraction from left to right:

$104 - 9 + 3 = \left(104 - 9\right) + 3 = 95 + 3 = 98$

Note
It is sometimes difficult to read the difference between 1 1/2 and 11/2. Especially for people who do not used mixed numbers very often (if ever).