for the second one, I estimated it as 1000×9.02=9020, so guessed the second one is larger

the first one is 9021001410
the second is 902289410

so the second one is slightly, slightly larger

2. on this one, the trick is to square both numbers…

square the square roots and get 10×5=50
square 7 and get 49

so the square roots are larger (if the square of a number is larger, its square root will be)

3. 3^5=3×3x3×3x3
5^3=5×5x5

so you can see the largest prime factor of the first is 3
and the largest prime factor of the second is 5