Today is February 29th, meaning that this year is a leap year. In the Gregorian calendar we use, there is an annual deviation of 6 hours between it and the Earth’s orbital period. Therefore, every four years, a leap day is added to correct this discrepancy, and that year is called a leap year. If the AD year is divisible by 4, it is a leap year. The presence of an Olympic Games is associated with leap years. To determine if a large number is divisible by 4, you check if its last two digits are divisible by 4. This year is 2024, so the last two digits (24) are divisible by 4. However, there is an exception to leap years; years divisible by 100 but not by 400 are not leap years. An example is the year 2100, which is divisible by 4 but not a leap year. However, the Olympics will still occur.

今日は２月29日、つまり今年は閏年(うるうどし)です。今私達が使っているグレゴリオ暦と地球の公転周期との間には毎年6時間のずれが生じます。そこで４年に１度閏日を設けてこのズレを修正します。その年が閏年です。西暦の年号が４で割り切れれば閏年です。閏年にオリンピックがあります。ある大きな数字が４で割り切れるかどうかは、その数字の下２桁が４で割り切れるかどうかで判定します。今年は2024年ですから、下２桁の24は４で割り切れます。しかし閏年には例外があって、年号が100で割り切れるが、400で割り切れない年は閏年ではありません。近いところでは2100年です。2100は４で割り切れますが2100年は閏年ではありません。オリンピックはあります。