When it says ‘three consecuitive odd numbers’ that means three odd numbers in a row. For example: 3,5,7 or 13,15,17. Since it skips an even number the difference is always 2 between one odd number and the next one. Now into the question.
It is asking for the smallest of the three consecutive odd numbers that add up to 81. First since its 3 consecutive, divide 81 by 3.
81/3 = 27
That number is now the middle number. To find the other two you add 2 for one and subtract 2 for the other.
27 + 2 = 29
27 - 2 = 25
You can check your work by adding
25 + 27 + 29 = 81
You now have your three numbers. When they are in order like above you can clearly see that 25 is the smallest number of the three.
Answer: 25