Adding and subtracting decimals word problems
On Saturday, William's parents gave birth to twins and named 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 is 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 7.27. So 7.27 plus 8.34. And it's always important that we line up the decimal. And I'd like to do the decimal first. So it's 8.34. And we'll just add these two up. So 7 plus 4, and this is really 7/100 plus 4/100 is 11/100, which is the same thing as 1/100 and 1/10. 1/10 plus 2/10 plus 3/10 is 6/10. We've got our decimal sign right over there. And then 7 plus 8 is 15, or you could even say it's five 1's and one 10. And we're done. They weighed 15.61 pounds in total.