Exercise 1 solution

7 C:  7 x 9/5 = 12.6; + 32 = 44.6 F (article: 45)
22 C: 22 x 9/5 = 39.6; + 32 = 71.6 F (article: 72)
25 C: 25 x 9/5 = 45; + 32 = 77 F (article: 77)
38 C: 38 x 9/5 = 68.4; + 32 = 100.4 F (article: 100)
All agree after rounding.

A range is a difference, not a reading. The +32 offset belongs only to thermometer readings. A 30 C difference is 30 x 9/5 = 54 F. Converting 30 C as a reading gives 86 F, which is what the article printed. (Its other difference, 10 C = 18 F, is done correctly.)