2, can be 2...: 18, 30, 46, 102 can be 5...: 30, 65.
3. Minimum value: 20, 18 Maximum value: 4,6.
4、6
5.A=24 B= 18 A and B's greatest common factor: 6, 6 A and B's least common multiple: 72,72.
6. Prime numbers: 1 1, 23, 29, 43, 53, 79, and composite numbers: 22, 27, 5 1, 72.
7、
(1), wrong. Natural numbers less than 3 are 0, 1 and 2.
(2) wrong. All positive integers, including 1, prime numbers and composite numbers.
(3) wrong. The coprime of two numbers is a prime number.
(4) wrong. The factors of 12 are 1, 2,3,4,6, 12.
(5) right.
(6) right.
8. The greatest common factor of 11and 7 is1. The least common multiple is 1 1×7=77.
The greatest common factor of 9 and 12 is 3. The least common multiple is 3×3×4=36.
The greatest common factor of 12 and 18 is 6. The least common multiple is 2×3×2×3=36.
The greatest common multiple of 13 and 15 is 13. The minimum common multiple is 13× 1×4=52.
The greatest common multiple of 18 and 24 is 6. The least common multiple is 2×3×3×4=72.
The greatest common factor of 15 and 25 is 5. The minimum common multiple is 5×3×5=75.
9、7×8+ 1
=56+ 1
A: So the next time they meet in the nursing home is May 3rd.
I didn't write the tenth question-