"This gives you a seven part scale:" The scale shown appears to have nine parts
vencu > vecnu
"...and translate in to Lojban." > "...and translate it to Lojban." or "...and translate into Lojban."
Exercise 3#4 includes "jufra", which is never introduced and does not appear in the vocab appendix. It's not actually a translation exercise, but it's rather annoying to have to run off and find a gismu list to find out what it means.
Exercise 4.6: "tavla" > "cusku" The answer is given as "You say strange things." {do tavla lo ba'e cizra} looks an awful lot (to me) like "You talk to strange things."