math  standard form
posted by chelsea on .
please could you check the first 2 then explain the method on the other 2
1)5.2x10^6 + 3x10^5
5200000+300000=5500000
5.5x10^6
2)4.2x10^5 + 1.28x10^6
420000+1280000=1700000
1.7x10^6
method please
3)6.5x10^3  3.5x10^9
0.0650.000000035=0.064999965
how do you convert this number into standard form?
4)400/(5x10^6)
i don't get how to work this one out
please could you help/explain. thanks.

You did 3) wrong. Using your method..
3)6.5x10^3  3.5x10^9
0.006 50.000 000 003 5=0.0059999965
5.9999965 x 10^3
Let me show you an easier way. Convert both numbers to the same power.
6.5E3  3.5E9
6.5E3  3.5E3E6
(6.5 .000 0035 )E3
6.499 99965 E3
another example
5.2x10^6 + 3x10^5
52.0E5+3E5
55E5 or 5.5E6
Lastly
4)400/(5x10^6)
4E2/5E6= .8E(26)=.8E4=8E5 
what does E stand for?

E means x 10^ It is often used in computers, calculators, and in ASCII chat as here. It is easier.