For those of you who need a refresher: Positive integers are all the whole numbers greater than zero: 1, 2, 3, 4, 5, ... . Negative integers are all the opposites of these whole numbers: -1, -2, -3, -4, -5, … . We do not consider zero to be a positive or negative number. For each positive integer, there is a negative integer, and these integers are called opposites. For example, -3 is the opposite of 3, -21 is the opposite of 21, and 8 is the opposite of -8. If an integer is greater than zero, we say that its sign is positive. If an integer is less than zero, we say that its sign is negative. Whew!
However, the kids did well, and their Chapter 23 tests reflected their efforts. Good job, students!
2 comments:
My daughter had a problem the other day. Round -0.325 to the nearest integer. My daughter rounded it to zero but the teacher said the correct answer is -1. Can you explain this?
Hi! This is not something we teach in our 5th grade curriculum, but if I'll try my best to explain what I understand.
There are actually many different ways of rounding negative integers.
1) Floor: rounding down to the next integer
x-1 < floor (x) < = x
2) Ceiling: rounding up to the next integer
x < = ceiling (x) < x+1
3) Truncate: round toward zero
trunc (x) = floor (x) when x > = 0
trunc (x) = ceiling (x) when x < = 0
4) antitruncate: round away from zero (rare)
trunc (x) = ceiling (x) when x > = 0
trunc (x) = floor (x) when x < = 0
In this case, let's use round-ceiling, which rounds towards positive infinity.
For instance, -0.3 is rounded to 0.
In the case of Round-Floor, which rounds towards negative infinity, the algorithm is Rounded Result=INT(Number).
In this case, -0.3 would be rounded to -1.
So your daughter's teacher is correct, with the Round-Floor example.
Good luck!
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