By Allison Horky Updated Aug 30, 2022
Finding the square root of a number means determining the value that, when multiplied by itself, reproduces the original number. For non‑perfect squares, the result is a non‑terminating decimal. Once the original number is fixed, its square root is immutable—changing it will produce a different product.
Begin by rounding the number you want to root to the nearest tenth. If the second digit after the decimal point is 5 or greater, round up; otherwise round down. For example, 15.37 rounds to 15.4 because the hundredths digit (7) is greater than 5. Repeat this process for as many decimal places as you need.
Clear the calculator display to avoid confusion, then type the rounded number (e.g., 15.4). Ensure that the screen shows only the value you intend to calculate.
Press the square‑root button (√ or “sq rt”). The display will show the approximate root. For 15.4, the result is 3.924. Notice that rounding the root itself (e.g., to 3.9) will change the squared value (3.9² = 15.21) and no longer reproduce the original rounded number. Therefore, the square root should not be rounded after the calculation.
