Lucas and Mitchell were asked to add the numbers 3.54 and 12.09. Lucas stated that he completed the addition problem by usi

Lucas and Mitchell were asked to add the numbers 3.54 and 12.09.

Lucas stated that he completed the addition problem by using the following method:

First, I broke the numbers apart. I broke 3.54 into 3.00+0.50+0.04 and 12.09 into 12.00+0.09.

Then, I combined 0.04 and 0.09 to get 0.13.

Next, I combined 0.13 and 0.50 to get 0.63.

Then, I combined 3.00+12.00 to get 15.00.

Finally, I added the decimal to get 15.63.

Mitchell stated that he completed the addition problem by using the following method:

First, I added the whole numbers to get 3.00+12.00=15.00.

Next, I added the numbers in the tenths place, 0.50+0.00=0.50.

Then, I added the numbers in the hundredths place, 0.04+0.09=0.013.

I then added 0.50 and 0.013 to get 0.513.

Lastly, I added the decimal to the whole number to get 15.513.

Determine if Lucas and/or Mitchell had a flaw in their method. If they did, correct the flaw(s) so that both the methods used are correct. PLZ ANSWER THE QUESTION!