Calvin may claim 2018 depreciation in the amount of $339.
Solution:
Given: Cost of the new desk = $2373
The recovery period of the new office desk is 7 years.
To find: Amount to be claimed on 2018 depreciation
We know, the rate of MACRS depreciation is 14.29% (Using the half-year convention)

MACRS is Modified Accelerated Cost Recovery System is the current tax depreciation system in the US.
Half-year convention is used to evaluate depreciation for tax purposes and denotes that the fixed assests will be considered to be in service for one-half of its first year, irrespective of actual purchase date.