welcome to math with Mr J [Music] this video I'm going to cover what cube roots are this will be an introduction to cube roots let's jump into number one where we have a 2 and an 8. now in order to understand cube roots we're going to start by looking at cubing a number which means we have an exponent of three for example let's start with 2 cubed so 2 with an exponent of three this means two times two times two which equals eight so 2 cubed equals eight again two cubed that means two times two times two two times two equals 4 times 2 equals eight now going off of 2 cubed let's move on to looking at a cube root now a cube root is the inverse of cubing a number which means the opposite of cubing a number we are going in reverse so to speak we need to think what number multiplied by itself three times will equal the number under the cube root symbol for example let's find the cube root of eight so what number multiplied by itself three times will equal eight well two the cube root of eight is two so again the cube root of eight equals 2. so we can see the relationship there 2 cubed equals eight and then the cube root of eight equals two let's move on to number two and take a look at another example we have 5 and 125. let's start by cubing five so five cubed and that does equal 125. so 5 cubed that means 5. times 5 times 5 which again equals 125. five times five equals 25 times 5 gives us that 125. now let's find the cube root of 125. so what number multiplied by itself three times will equal 125. well 5. 5 is the cube root of 125. so the cube root of 125 is 5. so to recap number two five cubed equals 125. five times five times five the cube root of 125 is 5 because we know 5 multiplied by itself three times will equal that 125. so we can see the relationship there between 5 cubed and the cube root of 125. let's move on to numbers three and four where we have two examples of cube roots starting with number three where we have the cube root of 64. so what number cubed will equal 64. well 4 4 cubed equals 64. four times four times four times four equals 16 times 4 equals 64. so the cube root of 64 is 4 we need to think what number multiplied by itself three times will equal the number under the cube root symbol lastly let's move on to number four where we have the cube root of 27 so what cubed equals twenty-seven three three cubed equals 27. three times three times three three times three equals nine times three equals twenty-seven so the cube root of 27 is 3. so there you have it there's a basic introduction to cube root just remember what number multiplied by itself three times will equal the number under the cube root symbol I hope that helped thanks so much for watching until next time peace foreign