a substance that tastes sour, reacts with metals and carbonates, and turns blue litmus red. e.g. lemon juice a logical rule or procedure that guarantees solving a problem to go to a specified place; to jump a number multiplied by a variable in a mathematical expression concerning the development or growth of a thing or person talk, conversation a negatively charged particle having limits; lasting for a limited time a material that can easily flow. e.g. water to cause, to persuade the distance between two points, numbers or times about or caused by combined atoms a device that receives information about space something that makes a change. a statement that can be proved a change changing from one form to another. e.g. changing from one language to another a quantity that has both size and direction. speed in a given direction