only if the first number is 4 (16 when squared) and the second is 3 (9 when squared)
It can be if the first number is x + 21 and the second is x for any number x.
To subtract a mixed number by a mixed number you first need to turn the fractions into improper fractions then you just subtract them as you would with the normal fractions
(-10) - (-5) = (-5) when subtracting a negative number from another negative number if the first number is larger that the second number then you just subtract the to numbers. don't worry about the signs just subtract the numbers when your done put the sign of the first number on again.
The inverse operation for subtract 5 is add 5. This is because whatever number you start with, if you first "subtract 5" and then "add 5" or if you first "add 5" and then "subtract 5" you are back to the number you started with.
if you want to subtract a bigger number from a smaller one, first subtract smaller number from bigger one add negative sign in front of answer you got
to find the square root of a number you can use the guess and check method which is kind of complicated to explain with just words but i will answer soon and try searching for "How to do the Guess and Check Method" on Google.com or Bing.com by Microsoft or Ask.com To find the square root of a number with a calculator you hit the weird division thingy... after the number/ before the number depending on type of calculator.
this is for restrictions. take the first number on your serial number and then subtract it by 1 then do that number then the first number and alternate
Subtract the number you first thought of.