Calculating numbers into scientific notation

[Starfish]

Can you help once again???

Question 7800nm + 95pm ??

My answer.....7800 x 10^-12 + 95 x 10^-9 = 7.8 x 10^-9 + 95 x 10^-9 = 7.8 + 95 = 102.8 x 10^-9m??

Please comment tell me where I have gone wrong

 

[mmm4444bot]

In scientific notation, the "first" number needs to be less than 10, but not less than 1.

7800 nanometers is 0.0000078 meters.

In scientific notation, that's 7.8 × 10[sup:2f5vxh9f]-6[/sup:2f5vxh9f] meters.

(7.8 is less than 10, but not less than 1, and the exponent -6 shows that we need to shift the decimal point in 7.8 six places to the left)
.

95 picometers is 0.000000000095 meters.

In scientific notation, that's 9.5 × 10[sup:2f5vxh9f]-11[/sup:2f5vxh9f] meters.

(9.5 is less than 10, but not less than 1, and the exponent -11 shows that we need to shift the decimal point in 9.5 eleven places to the left)
.

Did they ask you to report the sum in meters? From your work shown, that's the impression that I get.

       0.000007800000
  +    0.000000000095
-----------------------------
       0.000007800095

To write this result in scientific notation, we shift the decimal point in 0.000007800095 six places to the right to obtain 7.800095 because 7.800095 is less than 10, but not less than 1.

.

7.800095 × 10[sup:2f5vxh9f]-6[/sup:2f5vxh9f] meters

The exponent -6 means that we shift the decimal point six places to the left, to get the value 0.000007800095