Final answer:
To write numbers in scientific notation, express the number as a decimal between 1 and 10, multiplied by a power of 10. The power of 10 represents the number of places the decimal point moved.
Step-by-step explanation:
When writing numbers in scientific notation, the number should be written as a decimal greater than or equal to 1 and less than 10, multiplied by a power of 10. The power of 10 indicates the number of places the decimal point has been moved. Here are the numbers from the question written in scientific notation:
a. 654 = 6.54 x 102
b. 1234560 = 1.23456 x 106
c. 0.000000673 = 6.73 x 10-7
d. 0.002590 = 2.59 x 10-3
e. 200.4 = 2.004 x 102
f. 260.0 = 2.6 x 102
g. πr2, where r = 8.7 cm, can't be written in scientific notation as it is a mathematical expression and not a number itself.
h. 23.24 + 18.6 - 5 = 36.84.