It depends on your computational skills.
Your brain, of course.
easy to divide mentally
No, but if you practice you can learn to do it and it gets easier. Start of by learning (by rote) your times tables and when adding up do so in 10s.
Compatible numbers can easily be divided mentally.
Break it up into two separate problems. First 4X25=100, which is easy enough. Then 27X100=2700.
Compatible Numbers are numbers that are close in value to the actual numbers and easy to add, subtract, multiply or divide mentally
dont know about associative property but this one is easy in your head. 4x25=100x27=2700
arithmetic According to my son's homework, they are "compatible" numbers.
It is possible to compute numbers larger than can be written using normal mathematics. There is an algorithm that is used to compute the decimal expansion of pi. It is easy to compute the sum of all the counting numbers from one to 100. Add the highest and lowest, and you will get 101. Add the next highest, 99, and the next lowest, two, and you will again get 101. If you continue in this way to compute the sums, you will have the sum 101, computed 50 times. Now compute the product of 50 and 101, and you will get 5050. This is the sum of all the counting numbers from one to 100.
easy well not really
its derivative is easy to compute
Easy is when something can be done without much effort physically or mentally.
We make the compute learning easy. Shakeel
An easy way is to minus step by step eg: 111-28-9-56 111-28 then -9 then -56 OR 111-(28+9+56)
Doing it mentally, the easiest method is usually to pair the greatest with the least and add them up, then add the resultant numbers using the same method until you end up with the sum.
It is called the mode. An easy way to remember it is: most common-mode.
The numbers were mostly easy to carve into stone.
because they are whole numbers so are easy to deal with
The answer depends on your learning and expertise. For example, I had to learn my times table up to 30 times 10 and so I can do those multiplications easily. Most students nowadays do not learn tables for large numbers. Also, I completed my basic studies before calculators and computers were in widespread use and so relied on manual calculations and that gave me lots of practice in arithmetic. So computations that I might consider trivially simple may look difficult to others.