The Brainliest Answer!
Just learn first the formula of the basic of the that chapter .

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If you want full marks in math you have to revision you chapter and firstly you check your improvement in math.
Finding square roots by guess & check method

One simple way to find a decimal approximation to, say √2 is to make an initial guess, square the guess, and depending how close you got, improve your guess. Since this method involves squaring the guess (multiplying the number times itself), it actually uses the definition of square root, and so can be very helpful in teaching the concept of square root.