Question

What is 24388 in scientific notation? And. Give the answer to the following calculations in the proper number of significant figures? a. 25,30cm x 0.035cm.

Answer 1

To do scientific notation, place the decimal point to the right of the FIRST digit, then place a x 10, finally raise the power of 10 to a number to mentally move the decimal point to the correct number of places.
24388 = 2.4388 x 10^4

Here is a site that will give you the necessary information on significant figures.
http://www.chemteam.info/SigFigs/SigFigs.html