The idea is to round each of the numbers - in this case to the nearest multiple of 10 - then do the addition in your head.
If two numbers have a sum of 31 and a product of 228, then the two numbers are 12 and 19. Adding them will give you 31, and multiplying them gives you 228.
The result is called the sum of the two numbers. The operation of addition is commutative. This means that the addition of two numbers will give the same sum regardless of the order in which the numbers are added.
11 and 12
1 + pi, 1 - pi. Their sum is 2.
The idea is to round each of the numbers - in this case to the nearest multiple of 10 - then do the addition in your head.
The numbers are 26 and 28.
The numbers are 17 and 18.
Notice that each of the three numbers is rather close to 9,000. The estimated sum is 27,000.
The sum is where two or more numbers are added together to give a total.
The numbers are 4, 5 and 6.
Quantifying the sum of two numbers is usually simple to do. You take the given sum of the two numbers and subtract it with one given unsummed number. This will give you the other number.
210
the only two odd numbers are 57 and 59 which give a sum of 116
4 or 5 depending on which way the other numbers in the sum are being estimated.
55
They are 36 and 64