Our Math Monday blog assignment for today was to explain why numbers with negative exponents come out as decimals and not negative numbers. This concept seems pretty hard to grasp at first, but it's easy to understand once you get the hang of it.
In short, negative powers result in decimal numbers because the powers are not positive. Seems confusing, I know. When a base has a positive power, the number multiplies itself by however many the exponent calls for. However, when an exponent is negative, the number multiplies downward instead of upward, so we get a fraction, which can be written easily as a decimal. To simplify these exponents, carry them out as if they were positive powers and place the result in a fraction under 1. The negative sign only signifies that it will be a fraction. This is why 2^-5 is 1/32 rather than -32. -32 in exponential form would actually be (-2)^5. This can be figured out with a similar process.
This concept ties in with our current math unit on exponents because we're expanding what knowledge we already had of exponents and learning new concepts and principles used in exponents. It is also "layered" with our knowledge of positive and negative integers as well as our knowledge of fractions, decimals, and how they are interrelated.
In short, negative powers result in decimal numbers because the powers are not positive. Seems confusing, I know. When a base has a positive power, the number multiplies itself by however many the exponent calls for. However, when an exponent is negative, the number multiplies downward instead of upward, so we get a fraction, which can be written easily as a decimal. To simplify these exponents, carry them out as if they were positive powers and place the result in a fraction under 1. The negative sign only signifies that it will be a fraction. This is why 2^-5 is 1/32 rather than -32. -32 in exponential form would actually be (-2)^5. This can be figured out with a similar process.
This concept ties in with our current math unit on exponents because we're expanding what knowledge we already had of exponents and learning new concepts and principles used in exponents. It is also "layered" with our knowledge of positive and negative integers as well as our knowledge of fractions, decimals, and how they are interrelated.