teh4dp a { text-decoration: under; color: #0059ae; } History Singapore Pools started selling 4D bets in May 1986 on newly introduced computerised gaming systems. This move to utiliseWhen you play Permutation Bet, you cover all possible permutations of the 4D number you picked. For example, if you play Permutation Bet on 1133, you cover 1133, 1313, 1331, 3131,