Update exercises:
breuken_vergelijken_2.html
decimals_on_the_number_line_2.html
division_0.5.html
linear_equations_1.html
linear_equations_4.html
number_line_3.html
place_number_in_boxes.html
reading_bar_charts_2.html
tafel_van_12510.html
telling_time_interactive.html