A combination of dry erase linear 12/24 elapsed time rulers and conventional analogue clock face with a time table grid on reverse. The linear 12/24 hour analogue/digital elapsed time ruler enables students to calculate elapsed time in a simpler way by marking start and finish time using dry erase markers, therefore calculating start and finish time. Compare the difference and relationship between analogue and digital time using either the analogue (top) or digital (bottom) section of the rule. Ends clip together to show continuous time. Teachers demonstration board ruler same as students but 110cm x 13.5cm. Time A4 double sided dry erase boards for 12/24 hours and time table grid on reverse. Teachers demonstration time board same as pupil A4 but 52cm x 38.5cm. Made from durable plastic.