11
94 is the greatest two-digit whole number that when rounded to the nearest ten rounds to a two-digit number.
9999876
Six.
11 is the smallest 2-digit prime number and 97 is the greatest 2 digit prime number, so their difference is 86
It is 891.
99x9999=989901
9999
999999
9999 is the 4-digit number and 999 is the 3-digit number.
999999999999
-2
987654321
998.
9999
999,999,999,990
You will get the greatest product if you choose the greatest possible numbers in both cases, i.e., 9 x 99.