## anonymous 5 years ago what is half of 2^{40} ?

1. anonymous

$2^{40}$

2. anonymous

$2^{39}$

3. anonymous

could you show me how you got that ?

4. anonymous

sure.

5. anonymous

lets do a simpler one. $2^5=32$ half of 32 is 16 $2^4=16$

6. anonymous

ok

7. anonymous

now for the "math" half of $2^{40}$ means $\frac{2^{40}}{2}$

8. anonymous

when you divide you subtract the exponents, so you get $2^{40-1}=2^{39}$

9. anonymous

sorry im a little lost, why did u subtract 1 ?

10. anonymous

oh because the denominator was 2, and $2=2^1$

11. anonymous

oh i see

12. anonymous

and when you divide you subtract the exponents. $\frac{b^n}{b^m}=b^{n-m}$

13. anonymous

but forget about that for a second. power of two look like 2,4,8,16,32,64,128,...

14. anonymous

multiply by 2 to get the next one. so if you divide by 2 you get the previous one.

15. anonymous

alright then thank you :)!

16. anonymous

o wow