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.
compatible numbers
Your brain, of course.
It depends on your computational skills.
Break it up into two separate problems. First 4X25=100, which is easy enough. Then 27X100=2700.
No.
compatible numbers
benchmark numbers
Your brain, of course.
It depends on your computational skills.
Numbers like 10, 25, 50, and 100 are easy to compute mentally because they have simple multiples or divisions that are easy to work with. For example, doubling 25 is 50, or dividing 100 by 10 gives you 10. These numbers are often used as benchmarks in mental math calculations.
Break it up into two separate problems. First 4X25=100, which is easy enough. Then 27X100=2700.
No.
dont know about associative property but this one is easy in your head. 4x25=100x27=2700
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 numbers that are easy to compute mentally are called
if you mean multiplication then 4x25=100 x 27 = 270
easy to divide mentally