Capex is nothing but capital expenditure incurred for creating assets; different from expenditure in the course of a company’s operations (opex).
Here you are trying to reconcile if the expended capital matches with an increase in tangible assets and reduction due to depreciation. However, companies calculate depreciation on different items differently and capital expenditure need not create tangible assets. Goodwill is an example. 
This post is great for understanding capex.