Article: When a number has an exponent that means you multiply that number by itself as many times as the exponent says. To simplify any number that has an exponent simply multiply it the appropriate number of times.  For example: 43=4×4×4=64{\displaystyle 4^{3}=4\times 4\times 4=64}. If there is a negative sign and no parentheses, the exponent is simplified and then the negative sign gets added: −22=−(2×2)=−4.{\displaystyle -2^{2}=-(2\times 2)=-4.}  If there is a negative sign, but the number is in parenthesis, the negative number is part of the exponent: (−2)2=−2×−2=4.{\displaystyle (-2)^{2}=-2\times -2=4.} It may be confusing at first to see a variable with an exponent. Just remember, any variable with the same exponent number can be added or subtracted. If the letters are the same, but the exponents are different, they cannot be combined.  For example, 6x2+5x2=11x2{\displaystyle 6x^{2}+5x^{2}=11x^{2}}. Similarly, 4xy3−8xy3=−4xy3{\displaystyle 4xy^{3}-8xy^{3}=-4xy^{3}}. On the other hand, 5z+5z2{\displaystyle 5z+5z^{2}} cannot be simplified, since one variable has an exponent, and one does not. If two variables are being multiplied together and they both have exponents, you can add the exponents together to get the resulting exponent. This only applies to variables of the same letter. For example, (x2)(x3)=x2+3=x5{\displaystyle (x^{2})(x^{3})=x^{2+3}=x^{5}}. If you want to divide two variables that have exponents, simply subtract the bottom exponent from the top exponent. This only applies to variables that are the same letter. For example, a6a3=a6−3=a3{\displaystyle {\frac {a^{6}}{a^{3}}}=a^{6-3}=a^{3}}.

What is a summary?
Simplify exponents of numbers. Combine like terms with the same exponents. Add the exponents together when multiplying variables. Subtract the exponents when dividing variables.