Typos and fixes in Lessons 3, 4 & 5

3 lat temu · 6ea5048692
--- a/Lesson3/Lesson3.odp
+++ b/Lesson3/Lesson3.odp
--- a/Lesson3/Lesson3.pdf
+++ b/Lesson3/Lesson3.pdf
--- a/Lesson4/Lesson4.odp
+++ b/Lesson4/Lesson4.odp
--- a/Lesson4/Lesson4.pdf
+++ b/Lesson4/Lesson4.pdf
--- a/Lesson5/Lesson5.odp
+++ b/Lesson5/Lesson5.odp
--- a/Lesson5/Lesson5.pdf
+++ b/Lesson5/Lesson5.pdf