10/15 simplifies to 2/3 (divide the numerator and denominator by 5).
0.66666
1.5
66.6666667%
1.5
0.6667
1.5
2 over 3
17/21
3
Fifteen ten-thousandths as a decimal is 0.0015
1/6
They are equal. On ten over fiteen, divite ten by five and fifteen by five, it equals two over three.