The field area is 42 hectares. 5/6 of this area was sown with wheat and 3/7 of the remaining area was sown with rye.

In order to find the part of an integer value, you must divide it by the denominator of the fraction and multiply by its numerator.
Based on this rule, we determine how many hectares are allotted for wheat, provided that this is 5/6 of 42 hectares of the entire field:
42: 6 * 5 = 35 hectares.
3/7 of the remaining field is allocated for rye. Let’s find it:
(42 – 35): 7 * 3 = 3 hectares.