Which Way is Minus?
Product Description Reviews
19 minutes, Grades 5 and up
WHICH WAY IS MINUS? introduces and develops the concept of negative and positive. This colorful and simple video employs numerous animated illustrations to explain this concept. The idea that mathematics exists to describe the physical world is reinforced.
LESSON ONE begins by discussing opposites: up and down, right and left, etc. By way of several examples, the concept of negative and positive is introduced as a useful way to mathematically describe opposite directions. Positive and negative signs are introduced.
LESSON TWO examines the concept of zero as the starting point between positive and negative. The idea is emphasized that negative and positive signs describe direction and do not describe quantity.
LESSON THREE illustrates how to add and subtract positive and negative numbers by using real examples. The examples show that the initial designation of positive and negative directions is arbitrary and does not change the result. This concept is expanded to show why every sign in the mathematical description of a problem must be changed if the positive/negative direction is reversed.
LESSON FOUR shows how to multiply numbers that have signs. The distinction between numbers as factors and numbers with signs is explained. The different uses of the minus symbol and the rules for manipulating numbers with signs are explained.
