Calculate the element of this total amount of tax which relates to the first lease by applying the fraction: NPV1 ÷ TNPV to the total tax chargeable on the TNPV
Cyfrifo elfen y cyfanswm hwn o dreth sy’n berthnasol i’r les gyntaf drwy ddefnyddio’r ffracsiwn: GNP1 ÷ CGNP gyda chyfanswm y dreth sydd i’w godi ar y CGNP