It is difficult to calculate √50 exactly, but if you know that 7²=49 and 8²=64, you can immediately see that √50 is between 7 and 8 and especially close to 7. Change the number with the slider and see how the estimation works.
Number to find the square root of50
7² = 49, 8² = 64
√50 is between 7 and 8, and closer to 7 (about 7.07)