I'll do the first one to get you started.
We want to compare the two fractions 3/4 and 7/8. For now, let's assume they are equal. Chances are they aren't, but we'll assume they are until we know otherwise.
So we have this equation 3/4 = 7/8
Let's cross multiply to get 3*8 = 4*7. Check out the attached image to see what I mean about "cross multiply" if you're not sure.
The equation 3*8 = 4*7 turns into 24 = 28 after you simplify each side. Clearly both sides aren't the same so the equation is not true. Meaning that the original equation 3/4 = 7/8 is not true. The right side of 24 = 28 is larger, so the right side of 3/4 = 7/8 is larger
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Here's how it looks like listed out
3/4 = 7/8
3*8 = 4*7
24 = 28
The right side is larger, so we must change all the equal signs to less than signs
3/4 < 7/8
3*8 < 4*7
24 < 28
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So that is why 3/4 is less than 7/8
Alternatively, you can use your calculator to find that 3/4 = 0.75 and 7/8 = 0.875; comparing 0.75 and 0.875, we see that 0.875 is larger. Therefore 7/8 is larger.
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Final Answer: A less than sign