Question

Form the smallest and the greatest number of 4 digits using any four different digits with the condition
that the number 7 will be in the tens place. Repetition of digits is not allowed.​

Answer 1

Answer:

Megan,

Start by observing that the number must be in the 410's or in the 420's. If it is in the 410's then the last digit, call it d, must satisfy 410 + 2d + 5 = 429. If it is in the 420's d must satisfy 420 + 2d + 6 = 429.