Since the larger tooth has to be displayed, knowing that no matter how many zeros you add to the end of a decimal, the value of it will stay the same. 0.23 is 1 digit short that 0.195, so if you just add a 0 to 0.23, it make both of them have a digit in the thousandths place. Now it's easier to solve, 0.230>0.195.
I met a man with 7 wives....each wife had 7 sacks (7*7) = 49 sacks. each sack had 7 cats...(49 * 7) = 343 cats each cat had 7 kittens...(343 * 7) = 2401 kittens <==