Cópia de Fractions - basics - 1st part
Read the instructions under the applet...
In the upper applet click the numerator slider and then push arrow → on the keyboard, and look what happens.
Then make numerator to be equal 1, and change the value of the denominator. Look what happens now!
Change the values of both sliders...
Use check boxes for more explanations and adjustments. Then use sliders again...