Add 5 ft 9 in and 10 ft 11 in

Add the feet together and add the inches together.

5 ft + 10 ft = 15 ft

9 in + 11 in = 20 in

Now there are only 12 inches in a foot so we have more than a foot in inches so we move 1 foot over so we have

16 ft 8 inches

We know that 1 foot is 12 inches then, we change all quantities to inches to ease the calculations:

5 ft 9 in = 5 (12) + 9 = 60 + 9 = 69 inches

10 ft 11 in = 10 (12) + 11 = 120 + 11 = 131 inches

so we add:

5 ft 9 in + 10 ft 11 in

= 69 inches + 131 inches

= 200 inches

if we want the result in foot we divide:

= 200/12

= 100/6 = 50/3

= 16 ft 8 in