noun
last two digits; last two figures
Refers specifically to the final two digits of a number, often used in contexts like phone numbers, serial numbers, or lottery results.
当選番号の下二桁が「42」の方が対象です。
Those whose last two digits of the winning number are '42' are eligible.
電話番号の下二桁を教えてください。
Please tell me the last two digits of your phone number.
下三桁 refers to the last three digits, extending the pattern to a larger digit group.
Compound of 下 (しも, 'lower') + 二 (ふた, 'two') + 桁 (けた, 'digit'). The reading ふたけた is a combination of the native Japanese numeral ふた and the counter けた.