A way of approximating or estimating an answer is to round off using significant figures. You can then select and carry out calculations and round answers to the nearest significant figure.
We can use significant figures to get an approximate answer to a problem.
We can round off all the numbers in a maths problem to \(1\) significant figure to make 'easier' numbers. It is often possible to do this in your head.
Question
Find a rough answer to \(\frac{{19.4}}{{0.0437}}\)
We first round off both numbers to \(1\) significant figure (s.f.):
\(19.4 = 20 (1\,s.f.)\)
\(0.0437 = 0.04 (1\,s.f.)\)
So we now need to make the denominator a whole number. We can do this by multiplying both \(20\) and \(0.04\) by \(100\).
