Sum value by date

Yes you need to use the YEAR function

2017Exp =
CALCULATE (
    SUM ( XeroMasterExport[ActualExp] ),
    YEAR ( XeroMasterExport[Date] ) = 2017
)

HTH! :smileyhappy:

EDIT: Well you may need to use this instead if you are using any slicers that cause the above to give you blank

2017Exp =
CALCULATE (
    SUM ( XeroMasterExport[ActualExp] ),
    FILTER ( ALL ( XeroMasterExport ), YEAR ( XeroMasterExport[Date] ) = 2017 )
)