Question

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

Answer 1

First, we multiply

`(-3)/(5)*17=(-3*17)/(5)=(-51)/(5)`

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

`(-51)/(5)\approx(-50)/(5)\approx-10`

Then:

`(-3)/(5)*17\approx-10`

Now, with the second multiplication

`-(3)/(5)*(5)/(6)`

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

`-(3)/(5)*(5)/(6)=-(3)/(6)=-(1)/(2)`

Since the half of 1 is 0.5 then:

`-(1)/(2)=-0.5`

Then:

`-(3)/(5)*(5)/(6)=-0.5`