30
It means using only the first non-zero digit (rounded up if required), and replacing all other digits by zero.
Front end estimation is a quick method to find an estimate of sums and differences, however it is generally not more accurate than the answer produced by adding or subtracting rounded numbers. Take for example a pair of pants and a shirt that are $24.99 and $16.99, respectively. The correct total of these items would be $41.98. Using the method of adding rounded numbers would yield $42 - which is only two cents from the correct total. Front end estimation would yield $40 - which is $1.98 short of the correct total. The use of front end estimation is why stores sell things for $24.99 and $16.99, rather than $25 and $17. It is an open attempt to make the consumer think that they are paying for something at a lower price than they actually are.
Well, darling, front-end estimation involves looking at the leftmost digits to get a quick ballpark figure, then adjusting for accuracy. Rounding just gives you a rough estimate without considering the actual numbers. So, if you want a more precise estimate, front-end estimation and adjusting is the way to go.
Square roots are computed using the Babylonian method, calculators, Newton's method, or the Rough estimation method. * * * * * Or the Newton-Raphson method.
320+270 = 590; yes, it is reasonable.
Front end estimation is simpler but usually more crude.
When using front-end estimation, we add or subtract the front digits, and then adjust for a more accurate estimation by estimating the sum of the digits to the right of the decimal point.
It is 15.
When using front-end estimation, first you add the front-end digits. Then adjust by estimating the sum of the remaining digits. Then add the two values
by adding or subtracting the values of the digits in the front place
2.0638
By using front end estimation, the numbers that you start of with have only one significant digit. It is, therefore, nonsense to have an answer with loads of significant digits.
500 + 400 = 900
10 + 1 + 4 = 15
2000 x 200 = 400000
8000 + 3000 = 11000
8 + 11 = 19