Answer:
see explanation
Explanation:
a
the error she has made is in cancelling the values in the denominators.
When cancelling fractions, this is performed between values on the numerator with values on the denominator.
correct result is
×
( cancel the 3 and 15 by 3 )
=
×
=
--------------------
b
as an estimate, multiply the numerators and denominators, that is
=
=