## is3535 one year ago help

1. is3535

2.9x10^10 + 5.35x10^10

2. is3535

@freckles

3. is3535

@phi

4. phi

your problem is like a*x + b*x factor out the x (a+b) * x in your case the "decimals" are like a and b, and x is like 10^10

5. is3535

|dw:1442260989838:dw|

6. phi

yes, I know. Do you know how to "factor out" 10^10 ?

7. is3535

no

8. phi

ok do you know how to distribute the 10 in this: 10* ( 2 + 3) ?

9. phi

10*(2+3) can be written as 10*2 + 10*3 factoring out 10 "undoes" that we want to do that with your problem $2.9\cdot10^{10} + 5.35\cdot10^{10}= (2.9+5.35) \cdot 10^{10}$

10. phi

now use order of operations: do the operation inside the parens (i.e. add)

11. is3535

ok

12. is3535

13. phi

what do you get when you add 2.9 and 5.35

14. is3535

8.25

15. phi

8.25 so 8.25 * 10^10 if you want this in scientific notation, then you want the number "out front" to be 1 or bigger , but less than 10 8.25 is bigger than 1 and smaller than 10 so it's ok $8.25 \cdot 10^{10}$

16. is3535

do you want me to time it

17. phi

?

18. is3535

82.5x10^11

19. phi

you mean write it as 8.5x10^10 (with an "x" ?) I used a dot (or *) because in algebra we use x for variables. but anyway you write it , it means the same thing. 8.25 times 10^10 the answer is not 82.5 x 10^11 the answer is 8.25 x 10^10 which can be written as 82.5 x 10^9 (but this is *not* scientific notation because 82.5 is too big)

20. is3535

that my answer is 8.25 x 10^10

21. phi

yes

22. is3535

ok