accounting standard I want to know AS 10 calculate depreciation with example ?

After revision of life of asset
the formula should be
Written down value of asset/(Balance life of asset+revised additional life)

Here answer is
100000/10= 10000 is the Depreciation per year
after 4 years the company revised it's Life
I.e change in accounting estimate
So the new depreciation will be
60000 (WDV)/(4+4)
sry... 60000/(6+4)
I.e 60000/10= 6000 per year
Ask for any doubts

For first 4 years calculate depreciation as usual I.e asset value/no. of useful?Life years
after 4 years revise the life of the asset

point c

Which method do you want?
Straight line or Written down value?