Answer: The expression has 6 significant figures.
Explanation:
First =, we need to understand what significant figure is.
Here's the definition: each of the digits of a number that are used to express it to the required degree of accuracy, starting from the first non-zero digit.
For example: 3.56 has 3 significant numbers
23.51 has 4 significant figures
3.450 has 4 significant figures, because even if the 0 after the 5 is there, we can remove it and the number remains the same.
4.09 has 3 significant figures, because the 0 after the comma makes a difference.
To know how many significant figures the expression has we need to solve it first, so:
(6.635-1.321)*(1747.4)*(3.54-2.6) =
5.314*1747.4*0.94 = 8728.54
8728.54 has 6 significant figures.