Sentence math problems. Help please!?

1a. 36. 1b. 1 each, or 3. 2. 20=17+3 21= 2+19 22=17+5 23=no answer 24=19+5 25= 2+23 26=19+7 27=no answer 28= 17+11 29= no answer 30= 19+11 3. 1/2 sq. ft 4a. you'll have to do that with information I give you. 4b. 1 3/8 ft. 5. 2.15 inches.