Rational numbers on a number line – comparing and zooming in

MathematicsNumbers & ArithmeticAges 12–13

Two rational numbers a and b (entered as p/q or a decimal) are marked on a number line; the zoomed-in axis below is divided by their common denominator to show why a < b or a > b. Drag point a or b to change its value (snapping to the tick marks), view the decimal form, and see that the midpoint (a+b)/2 is always a rational number lying between the two.