1 If natural numbers A and B satisfy a divided by b=7, then the greatest common factor is (b) and the smallest common factor (multiple) number is (a).
If A is a factor of B, then the greatest common factor of A and B is (A) and the least common multiple is (B).
3a = 2x2，b = 2x3x3，c = 2x3x5。 The greatest common factor of these three numbers is (2) and the least common multiple is (60).
The sum of two consecutive even numbers is 82. These two numbers are (40) and (4 2) respectively. Their greatest common factor is (2) and their least common multiple is (840).
5 has two integers, the smallest common multiple is 252, and the largest common factor is 12, one of which is 36 and the other is (84).
Multiple choice
6.A is a natural number except b= 13, and the least common multiple of a and b is (b).
13
7. Two-digit numbers. His two numbers are both composite numbers and coprime, and the least common multiple of these two numbers is 72. There are such numbers (I don't know what a composite number is and what a coprime is).
A 4 b 3 c 2 d 1
8 Known number A = 3x5x7xxa, number B = 2x5x7xxa.
The maximum factor of 1 A and b is 70, then a=(a).
The least common multiple of 2 A and b is 630, then a=(b)
a 2 b 3 c 5 d 7
answer the question
9. Find the greatest common factor and the least common multiple of the following groups by short division.
1, 45 and 54 2, 44 and 143 3, 16, 24 and 32
1、45=5*3*3
54=2*3*3*3
The greatest common factor is 9.
The least common multiple is 5*2*3*3*3=270.
2、44=2*2* 1 1
143= 13* 1 1
The greatest common factor is 1 1.
The least common multiple is 4 *13 *11= 572.
3、 16=2*2*2*2
24=2*2*2*3
32=2*2*2*2*2
The greatest common divisor is 8.
The least common multiple is 2*2*2*2*2*3=96.
10, X factory purchases a batch of raw materials according to different days. Type A purchases every 12 days 1 time, and b 15 days. If two kinds of materials are purchased at the same time, how many days does it take to purchase at the same time?
A=3*4 B=3*5
The least common multiple is 3*4*5=60.
So 60 days