**Option 1. **

1. Write down in symbolic language the statement:

a) the number 99 is an integer; b) the number -99 is not a natural number;

c) 15.21 is not an integer; d) 71 is a natural number.

2. Define by enumeration of elements the set of values p, at which the double inequality will be true:

a) -5 < n < 3; b) -6 < n < 0; c) |n| ≤ 3; d) |n| < 2.

3. Let the set A be prime two-digit numbers. Specify some three subsets of the set A.

4. Given sets A = {9; 12}, B = {3; 9; 15}, C = {3; 6; 9; 12}. Write in symbolic language:

a) the intersection of sets A and B; b) the intersection of sets A and C;

c) intersection of sets B and C; d) intersection of sets A, B and C;

e) union of sets A and B; f) union of sets A and C;

g) union of sets B and C; h) union of sets A, B and C.

**Option 2. **

1. Write in symbolic language the statement:

a) The number 54 is an integer; b) The number -12 is not a natural number;

c) 32.2 is not an integer; d) 49 is a natural number.

2. Define by enumeration of elements the set of values of n, at which the double inequality will be true:

a) -7 < n < 1; b) -9 < n < 0; c) |n| ≤ 5; d) |n| < 4.

3. Let the set A be prime single-digit numbers. Specify some three subsets of the set A.

4. Given sets A = {5; 10; 15; 20}, B = {5; 15; 25}, C = {10; 15}. Write in symbolic language:

a) the intersection of sets A and B; b) the intersection of sets A and C;

c) intersection of sets B and C; d) intersection of sets A, B and C;

e) union of sets A and B; f) union of sets A and C;

g) union of sets B and C; h) union of sets A, B and C.