noun
making the numbers balance; number-juggling; padding the numbers
Often implies adjusting or manipulating figures to meet a target, or including extra people/items just to reach a required count. Can be used in contexts like vote-gathering, budgeting, or team formation.
予算の数合わせに苦労した。
We struggled to make the budget numbers balance.
彼はただの数合わせでチームに入れられた。
He was put on the team just to make up the numbers.
帳尻合わせ focuses on making accounts or final totals match, often in a bookkeeping sense, while 数合わせ is broader and can refer to any situation where numbers need to be adjusted or filled.
頭数 means 'head count' and is neutral, whereas 数合わせ often carries a nuance of artificial adjustment or padding.
Compound of 数 (かず, 'number') and 合わせ (あわせ, 'matching' or 'adjusting'), from the verb 合わせる (あわせる, 'to match').