a(7+8):2=7.1
(7+1:):2=4.0
(8+1):2=4,1
b)(2.5+2.6):2=2.55
(2.5+2.7):2=2.6
(2.6+2.7):2=2.65
c)(3+3.85):2=3.425
(3+3.35):2=3.175
(3.85+3.35):2=3.6
d)(2.335+0.85):2=1.5925
(2.335+1.935):2=2.135
(0.85+1.935):2=1.3925
e)(2.3+3.16):2=2.73
(2.3+4.26):2=3.28
(3.16+4.26):2=3.71
f)(60.2+62.2):2=61.2
(60.2+64.2):2=62.2
(62.2+64.2):2=63.2