<Li> An electron's mass is about 0.000 000 000 000 000 000 000 000 000 000 910 938 356 kg . In scientific notation, this is written 6969910938355999999 ♠ 9.109 383 56 × 10 kg (in SI units). </Li> <Li> The Earth's mass is about 5972400000000000000000000 kg . In scientific notation, this is written 7024597240000000000 ♠ 5.9724 × 10 kg . </Li> <Li> The Earth's circumference is approximately 40 000 000 m . In scientific notation, this is 7007400000000000000 ♠ 4 × 10 m . In engineering notation, this is written 7007400000000000000 ♠ 40 × 10 m . In SI writing style, this may be written "7007400000000000000 ♠ 40 Mm" (40 megameters). </Li> <Li> An inch is defined as exactly 25.4 mm . Quoting a value of 25.400 mm shows that the value is correct to the nearest micrometer . An approximated value with only two significant digits would be 6998250000000000000 ♠ 2.5 × 10 mm instead . As there is no limit to the number of significant digits, the length of an inch could, if required, be written as (say) 6998254000000000000 ♠ 2.540 000 000 00 × 10 mm instead . </Li>

1 1+ h where h 0 is any real number