How much does it cost? Student activity Play

How much does it cost? Whiteboard exercise Play

How much does it weigh? Student activity Play

How much does it weigh? Simulation Play

How much does it weigh? Animation Play

How much does it weigh? How much does it cost? Student activity Play

How much does the notebook cost? Whiteboard exercise Play

How much does the stamp cost? Simulation Play

How much does the ticket cost? Whiteboard exercise Play

Inverse operations Whiteboard exercise Play

Inverse operations Student activity Play

Lena's number Whiteboard exercise Play

Letter symbols in equations, formulas and functions Whiteboard presentation Play

Letter symbols in equations, formulas and functions Class activity Play

Letters in equations Student activity Play

Letters in equations Whiteboard exercise Play

Linear equations Student activity Play

More difficult exercises Student activity Play

On the balance Whiteboard exercise Play

One equation, two unknowns Whiteboard exercise Play

One equation, two unknowns Student activity Play

Quadratic inequalities with one and with two unknowns Animation Play

Quadratic inequalities with one and with two unknowns Student activity Play

Quadratic inequalities with two unknowns Whiteboard exercise Play

Quadratic inequalities with two unknowns Simulation Play