The ancient Egyptians called the fraction with the numerator 1 the Egyptian fraction. For example, 2/5 is represented by1/3+115; 3/7 is represented by1/4+1/7+1/28.

∵ 1= 1- 1/2+ 1/2- 1/3+ 1/3- 1/4+ 1/4- 1/5+ 1/5- 1/6+ 1/6- 1 /7+ 1/7- 1/ 8+ 1/8- 1/9+ 1/9- 1/ 10+ 1/ 10=( 1- 1/2)+( 1/2- / kloc-0//3)+( 1/3- 1/4)+( 1/4- 1/ 5)+( 1/5- 1/6)+( 1/6- 1/7)+( 1/7- 1/8)+( / kloc-0//8- 1/9)+( 1/9- 1/ 10)+ 1/ 10= 1/ 2+ 1/6+ 1/ 12+ 1/20+ 1/ 30+ 1/42+ 1/56+ 1/72+ 1/90+ 1/ 10

These natural numbers are: 2,6, 10,12,20,30,42,56,72,90.