Answer:
x = 133
Step-by-step explanation:
Supplementary angles add to 180 degrees. Call the unknown angle x
47 +x = 180
Subtract 47 from each side
47-47+x =180-47
x = 133
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.
The answer to the equation is the second option.