A Cool 2 Digit Recurring Number Trick Here is a cool 2 digit recurring number trick. Super simple, have some fun! Think of any 2 digit number. Example: 58 Multiply that number with x 3 x 7 x 13 x 37 58 x 3 x 7 x 13 x 37 = 585858 And there we go, another cool simple recurring maths trick!