This question requires a knowledge of the equilibrium equation as well as a little understanding of the meaning of exponents.
The equilibrium equation is defined as K = product concentrations divided by the reactant concentrations...K = [product]/[reactant]. If K is a large number (one with a positive exponent) then the amount of product will be large compared to the amount of reactant. If K is a small number (one with a negative exponent) then the amount of product will be small compared to the amount of reactant. The only way that the amount of product would equal the amount of reactant is if K = 1.
Exponents are just a shorthand way of expressing large or small numbers. The number 103 is really just ten multiplied by itself 3 times...10 x 10 x 10 or 1000. Negative exponents, such as 10-3, represent numbers that are smaller than 1 and are really just fractions...1/10x10x10 or 1/1000. What all of this means is that when a negative exponent increases in magnitude, it represents a smaller and smaller number...10-5 is a smaller number than 10-2.