## Task 1

All pioneers compete in good deeds for the Day of the Republic. Class 1a has collected 12 marks worth of recyclables.

Class $1 \mathrm{~b}$ achieved 5 marks less.

How many marks did Class $1 \mathrm{~b}$ donate?
$12-5=7$. Class $1 \mathrm{~b}$ donated 7 marks.