Mental math is something that can be done i your head.
for example you can do 1+1 in your head and you dont need a calculator or paper to do it so i would be called mental math
Hope this helps
remember if you ever need anything and you dont want to waste points you can just post it on my pfp or message me the question
Answer:
She did not establish that heights are the same.
Step-by-step explanation:
I just answered it.
Answer:

Step-by-step explanation:
Subtract v from both sides

Simplify

Switch sides

Group like terms

Subtract the numbers: 2 - 42 = -40

Add 40 to both sides

Simplify

Divide both sides by 7

Simplify
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Answer: The answer is the 3rd one