Isabel is thinking of an even number between 234 and 250 . the sum of the digits is double the digit in the ones place. what is isabel's number ?

Since the required number is between 234 and 250, then the first digit of the number is 2 and the second digit can either be 3 or 4.

Let the second and the third digits be x and y respectively, then

2 + x + y = 2y

Consider when the second digit is 3, then

2 + 3 + y = 2y
5 = y

Thus, the number is 235.

Similarly, consider when the second digit is 4, then

2 + 4 + y = 2y
6 = y

Thus, the number is 246.

Since the required number is an even number, therefore, Isabel's number is 246.