Write all the possible factors of these pairs of numbers. Circle the common factors and select the highest common factor.

Here are the solutions to the problems from the image.

Creative Section B: Let's find the digit in the blank space of the following numbers so that the number formed is divisible by 11.
We use the divisibility rule for 11: a number is divisible by 11 if the difference between the sum of its digits at odd places (from the right) and the sum of its digits at even places (from the right) is either 0 or a multiple of 11. We assume the dots represent a single blank digit $x$.

• a) 27.......3 Let the number be $27x3$.

  Step 1: Sum of digits at odd places