Question

which is the best estimate of -3/5 times 17 and 5/6

Answer 1

First, we multiply

$\frac{-3}{5}\times17=\frac{-3\times17}{5}=\frac{-51}{5}$

We can approximate -51/5 to -50/5, like this:

$\frac{-51}{5}\approx\frac{-50}{5}\approx-10$

Then:

$\frac{-3}{5}\times17\approx-10$

Now, with the second multiplication

$-\frac{3}{5}\times\frac{5}{6}$

As five appears multiplying in both the numerator and the denominator, we can cancel it

$-\frac{3}{5}\times\frac{5}{6}=-\frac{3}{6}=-\frac{1}{2}$

Since the half of 1 is 0.5 then:

$-\frac{1}{2}=-0.5$

Then:

$-\frac{3}{5}\times\frac{5}{6}=-0.5$