Jayden wants to lay sod on his front yard and on half of his back yard. his front yard has a length of 50 feet and a width of 80 feet. his back yard has a length of 10 feet and a width of 30 feet. how many square feet of sod does jayden need to purchase?

The first thing we must do for this case is to calculate the area of both yards.
 We have then:
 front yard:
 A1 = (50) * (80)
 A1 = 4000 feet ^ 2
 Back yard:
 A2 = (10) * (30)
 A2 = 300 feet ^ 2
 "Jayden wants to lay sod on his front yard and on half of his back yard"
 Then, the total amount will be:
 A = A1 + (1/2) A2
 Substituting:
 A = 4000 + (1/2) (300)
 A = 4000 + 150
 A = 4150 feet ^ 2
 Answer:
 jayden needs to purchase 4150 square feet of sod