6th grade Math: write the phrase as an expression: twice a number z. My son didn't know if they meant 2 times z, or z times itself twice. I'm pretty sure the answer is 2z, but not sure how to tell him why.

Question

6th grade Math: write the phrase as an expression: twice a number z.  My son didn't know if they meant 2 times z, or z times itself twice.  I'm pretty sure the answer is 2z, but not sure how to tell him why.

alexandervonhumboldt2 · Answer

ok let z be a number. twice  z. twice=2. thus z+z=?

anonymous · Answer

Thank you.  I always thought math got cumbersome when taken out of context.  I'd rather see them working with simple equations than partial ones.

whpalmer4 · Answer

yes, "twice a number $z$" is the same as $2z$

"a number $z$ multiplied by itself" or "a number $z$ times itself" is $z*z = z^2$ 

"a number $z$ times itself twice" is actually $z*z*z=z^3$ but probably someone saying that means $z*z=z^2$