Mr and Mrs Wallace hire a van for moving house. They see this advert in the local paper and decide to use this company. When they hand the van back, their bill comes to £59. How many hours did they ...

"Even the +, −, =, and x signs we take for granted only came into widespread use in the 17th century. Which means that the earlier algebraists we know of … all had expressed their equations mostly in ...

Melting and freezing are both physical changes, which are often easy to reverse. To reverse this process, the water would need to be cooled enough until it freezes back into ice. This works because ...