Today I am going to explain how to estimate the square root of 89. First we need to set the barriers the square root of 81 is to the left, and the square root of 100 is to the right.  We know that the square root of 81 one is 9 and the square roost of 100 is 10. So between those two is 9.5. We need find out what square root is 9.5. First  we need to find the middle first we find out the gap between 81, and 100. The gap is 19  so we cut 19 in half and then we get 9.5. Next we add 9.5 to 81 and get 90.5 now that we have found the middle we will see how close the square root of 89 is to the middle of the barriers. So we estimate how far away it is some were around 9.4. Now we put it in our calculator, and get 9.43 so we were almost spot on.