Let the smallest natural number be 'x'.
Since the numbers are consecutive natural numbers, the seven consecutive numbers are:
\[ x, x+1, x+2, x+3, x+4, x+5, x+6 \]
The sum of these seven numbers is given as 133.
\[ x + (x+1) + (x+2) + (x+3) + (x+4) + (x+5) + (x+6) = 133 \]
Combine the 'x' terms and the constant terms:
\[ 7x + (1+2+3+4+5+6) = 133 \]
Calculate the sum of the constants:
\[ 1+2+3+4+5+6 = 21 \]
So the equation becomes:
\[ 7x + 21 = 133 \]
Now, solve for 'x':
Subtract 21 from both sides:
\[ 7x = 133 - 21 \]
\[ 7x = 112 \]
Divide by 7:
\[ x = \frac{112}{7} \]
\[ x = 16 \]
The smallest natural number is 16.
We can check this: The numbers are 16, 17, 18, 19, 20, 21, 22. Their sum is \( 16+17+18+19+20+21+22 = 133 \).
Ответ: 16