Checking arithmetic instead of scope
Verifying that a bid adds up while missing what it has left out.
General contractors, subcontractors and construction managers

For Developers, Owners & Public Entities
Estimating work may support an owner’s evaluation of budgets, proposals or disputed values, depending on the engagement.
An estimating review may consider scope, quantities, resource assumptions, pricing sources and available comparisons. Differences among estimates may raise questions for further evaluation; neither a low price nor a detailed calculation alone determines the outcome.
The same discipline applies to a budget being set, a change proposal being evaluated, and work already performed whose value is contested, though the last depends heavily on what the project recorded at the time.

Possible assignment considerations
Take quantities from the drawings on the owner's own account rather than checking the bidder's arithmetic.
Assemble crew, production, equipment and material assumptions visibly so a submitted price can be tested against them.
Treat material divergence from a bid as information about how the scope has been read.
Record assumptions, allowances and exclusions so the estimate can be relied on and challenged on the same terms.
Considerations and limitations
Verifying that a bid adds up while missing what it has left out.
Pricing assumptions or scope differences whose significance depends on the proposal, contract and project facts.
Without visible quantities, rates and assumptions, an estimate is hard to check or compare.
Estimating Assistance
Also in this practice