Yes the educated Romans were able to add and subtract mentally but for more complicated calculations they would use an abacus calculating device.
For example - 1V = _____ II is 2 1V is 4 so 4 - 2 --------- 2 ---------- so to subtract u must first have the two numbers u add the same way if u add you will get 6
does how many mean add or subtract
So that you only have to add/subtract the numerator which makes it much easier.
so they could add subtract count etc
So its easier to add subtract or most commonly multiply
Because you can't add or subtract fractions that have different denominators. Making them like fractions, by multiplying so the denominators are the same, you can add and/or subtract them.
IT looks like the operations is "add 4 subtract 3, add 5 subtract 2, add 6...". So the next step would be to subtract one. That would make the next number 11.
You can only add or subtract like terms. So, you subtract 9x from 2x, which gives you -7x. Then subtract -9 from 3 to get -6. And you are left with -7x -6.
he fact that they are improper is irrelevant. Re-scale the fractions so that they have the same denominator and thenadd or subtract as required.
If you add, subtract or multiply rational numbers, the result will be a rational number. It will also be so if you divide by a non-zero rational number. But division by zero is not defined.
so you see, first you multiply 5 and 6 then subtract 15 add 2 more and subtract 17 byee
Add the second negative to the first negative, so -1 - -2 = 1