Square root

How do you check square root from a number? Or you only use a calculator?

Use untitled script pic (22), replacing the "#" with whatever number you're finding the square root of.

In some sense it something like "calculator option" :

I don't understand.

Square root option in calculator:
image

I used to know how to do it on an abacus!

Here's Newton's method for sqrt(n):

  1. Make an initial guess, g.
  2. Compute the average of g and n/g. This is your new guess g.
  3. Repeat step 2 until g2 is close enough to n.

There are various ways to improve on this technique, but basically this is what calculators do. See SICP 1.3 for some of the improvements.

for BH: Interesting,

Check this link, 4 methods to calculate square root

Yeah, that long division one is more or less how you do it on an abacus.

Interesting!

Wasn't this called the Babylonian method?

I'll take your word for it, but I'm not familiar with the name.