The minuend minus the subtrahend equals the difference.
Tips
memory
In subtraction Chinese has a clean three-term vocabulary: 被减数 (bèijiǎnshù, minuend — what's being reduced), 减数 (jiǎnshù, subtrahend — what's taken away), 差 (chā, difference — what's left). The 被 prefix marks the passive 'thing being acted on'.