Calcular cuántos números de tres cifras se pueden formar con los dígitos 2, 3, 5, 7 y 9, sabiendo que el 5 no puede ser el número inicial.
+37146 Calculate how many three-digit numbers can be formed with the digits 2, 3, 5, 7 and 9, knowing that 5 cannot be the starting number.
First digit 4 choices (cannot use 5)
second digit 5 choices
third digit 5 choices
4 x 5 x 5 = 100 three-digit numbers (assuming numbers can repeat and the number cannot begin with'5')
