In principle, different standard contracts follow different rules of how to deal with mathematical errors found by the Contract Administrator during the checking of tender returns.

In JCT, the rule is that you’ll follow what’s stated in the bill, rather than the drawings. The specific guidance for this can be found in JCT Practice Note 2012.

The correction of any inconsistencies that may be found in the contract documents, is provided for with the simple statement that they shall be corrected and if this involves a variation, valued as such, leaving every case to be treated on its merits. The question of precedence is dealt by the statement that the contract conditions shall prevail over all others, leaving by implication the accepted convention that

• Drawings take precedence for location
• BoQ for quantity
• The Specification for quality.