Addition

Adding Using Front End Estimation of Sums

 

Adding using Front End Estimation of Sum

When finding the sum of several numbers, one
way to estimate the sum is called "front-end' 
estimation.

In front end estimation of sum you add only the
first digit of the numbers. The other digits are
replace by zeros.  Example:

Add 5524 and 3452 using front end estimation of sum.

Front end addition

Front-end estimation always gives a sum
less than the actual sum.

Normal addition