Why is the sum of two rational numbers always rational?
select from the drop-down menus to correctly complete the proof.

let a/b and c/d
represent two rational numbers. this means a, b, c, and d are (integers/irrational numbers? )
and (b is not 0, d is not 0/ b and d are 0? )
the
sum of the numbers is
ad+bc/bd, where bd is not 0. because integers are closed under (addition and multiplication/ addition and division? )
the sum is the
ratio of two integers, making it a rational number.

Use the spider tool located on page 1 of this activity to draw a 12-pointed star for the new logo. (hint: if the spider rotates 360 degrees -- or 720 degrees or 1080 degrees -- she will be facing in the same direction in which she started. when the spider is done drawing, you want her to be facing in the same direction in which she started. she'll be making 12 rotations, all the same size, so each rotation must be some multiple of 360/12 = 30 degrees.) urgently. been stuck on this problem for around 45 minutes now.! it should be easy if you're smart enough