Adding decimals word problem

on Saturday William's parents gave birth to twins and name them Nadia and Vanessa when they were first born Nadia weighed 7.27 pounds and was 21.5 inches tall and Vanessa weighed 8.34 pounds how much did the babies weigh in total so they tell us Nadia weighed 7.27 and Vanessa weighed 8.34 we have to add those up and really they just gave us this the length of Nadia at Birth really as a distraction just so that we just don't mindlessly add any numbers we see so this is really unnecessary information just to distract us so we need to add Nadia's birth weight plus Vanessa's so it's seven point two seven so seven point two seven plus eight point three four and it's always important that we line up the decimal and I'd like to do the decimal first so it's eight point three four and we'll just add these two up so seven plus four and this is really seven seven hundredths plus four hundredths is eleven hundreds which is the same thing as one hundredth and 1/10 1/10 plus two tenths plus three tenths is six tenths we've got our decimal sign right over there and then seven plus eight is fifteen or you could even say it's five ones and 1/10 and we're done they weighed 15.6 one pounds in total