Why is the greatest common factor of 2 numbers sometimes 1

There are equal numbers of both red and black cards in a deck of 52. 1) what is the probability that I randomly select a red card? 2) if I keep the red card, what is the probability of me selecting another red card?

Solve the equation: 4m - 7 = - 19

The product of 17 and 1.27

The number of employees of a company decreased from 225 to 189. Find the percent decrease

Using the distributive property to transform 4 (x + 3) = 3 (3x - 1) how do I substitute 3 for x to see if it's a true statement?

The measure of the larger of two complementary angles is 6° less than twice the measure of the smaller angle. Find the degree measure of each angle

The sum of an 84 number series is - 7980 what is the sum of the first and last the numbers

What is 3/4 times 1/2 and what is 1.5 times 0.75 and then i need to figure out how much bigger the answer is to 1.5 times 0.75 is to 3/4 times 1/2

10 (x+3) - (-9x-4) = x-5 + 3

1/7 divide by what is equal to 14?