1. The additive identity is 0. This is because adding 0 to anything leads to the same value. Example: 0+3 = 3.
2. An equation is where you have two expressions separated by an equal sign. In your case it would be "a mathematical sentence whose verb is 'equal' (=)"
3. The multiplicative identity is 1. Multiply 1 with any number and the result is that same number. Example: 1*7 = 7.
4. An open sentence is an equation that contains one or more variables. An example would be x+2 = 4. The reason why we call it open is because the true or false nature of the sentence is up in the air until we know what x is. If we knew that x = 3 for instance, then x+2 = 4 would be false since 3+2 = 4 is false. If we nailed down what x was then it would go from open to closed.
5. The symmetric property is that if a = b then b = a. Think of a mirror how the image reverses.
0.20 would be the answer.
The number places on a number go as follows starting at 0. and going to the right
ones, tenths, hundredth
This means that 0.00 is the hundredth place (the bolded 0). Since you round a 9 up one, this makes the 1 in the tenths place go to a 2 and the hundredth go to a 0
The solution is in the attached file
Let the two numbers be x and y.
x + y = 86
+
x - y = 12
_________
2x + 0 = 98
__________
2x = 98
x = 98/2
x = 49
From x + y = 86
49 + y = 86
y = 86 - 49
y = 37
The numbers are 49 and 37.
Yes.
This is the same thing as:

How many times can 6 go into 36?
6 times
Try:
6*6=36
So true.
Hope this helps! :D