These five nonagenarian’s greatest gift are good genes.

Five well-seasoned siblings — all older than 90 years — are making the years count as they gathered to celebrate their oldest brother’s 98th birthday last weekend in Iowa, according to KCCI.

Harold Hoyle, 98, was surrounded by his four younger brothers and sisters, who all sported a pink or blue t-shirt indicating their respective ages in the middle of a playing card to pay homage to a popular book series that shares their namesake.

“We always joke about their last name by saying ‘According to Hoyle,’ the book of rules for card games, thus the playing card on the shirts with each having one with their age on it,” Harold’s daughter Pam Anderson told the outlet.

The “According to Hoyle” series offers players a guide on how to play — and win — any game from poker to chess and backgammon.

In a picture taken together in Ankeny, Gayle Brietske, 92, and Genevieve Sherman, 97, both wore pink shirts with the playing card with their ages in the center, as Lowell Hoyle, 93, Lyle Hoyle, 95, and Harold wore matching blue shirts.