I think it would be the Multiplication property of equality
Yes; his answer is correct.
John can do this by multiple ways, but most likely he just remembered this one. Here are some ways.
1. He used his fingers; he put 1 finger, then another finger, and got 2 fingers up. The answer is 2.
2. He remembered it; usually Kindergarteners learn this and this is very easy to remember.
3. He used the things around him; I have 1 crayon then add another, how many do I have? 2.
Answer:
This question really shouldn't be here but Brainly doesn't have a app for the PC, only for mobile. You can only use the website for PC.
Answer:
a. Let x = hours surfing and let y = hours lifting weights
b. x + y = 6
c. 100x + 75y = 500
XY = −1−(−10) = 9
(line x = −5) = −5−(−9) = 4
Area = 1/2 * 9 * 4 = 18