From the abacus to the slide rule, tools for calculating have been around since ancient times. But it wasn’t until the 1970s — when many companies began introducing handheld calculators — that K–12 ...

Calculating probabilities How to describe probabilities and the probability scale Learn about probability, the probability scale and how to express probabilities with this BBC Bitesize Maths article.

Bethany Rittle-Johnson, Kerry G. Hofer, Emily R. Fyfe, Dale C. Farran, Early Math Trajectories: Low-Income Children's Mathematics Knowledge From Ages 4 to 11, Child Development, Vol. 88, No. 5, ...