so 1 mol of water in 18 grams of water
so 6.02 times 10^23=18 grams
divide by 18
one way is (6.02/18) times 10^23=0.33444 times 10^23
scientific notation is number more than 1 but less that 10 so
0.33444 times 10=3.344
so take 1 ten from the 10^23 to make 10^22 so
2 sig figs which are non zero numbers
3.3 times 10^22