Answer and analysis:
The essence of this problem is to divide the six numbers 1, 2, 3, 4, 5 and 6 into three groups, and each group has two numbers to form a two-digit number, so that the sum of the two digits is equal to twice that of the third digit. By the way, it is an important skill to turn interesting problems in life into pure mathematical problems. Students should pay attention to strengthening this ability from an early age, so as to use mathematical knowledge to solve difficult problems in practical work in the future.
By careful observation and bold attempt, we can get three numbers by grouping these six numbers: 12, 34, 56, because
12+56=34×2
That is, the age of these three trees is12,34,56. There are several different answers to this question. Please use your head and find another answer.