10-^2 or 0.01 one hundredth 10-^3 or 0.001 one thousandth 10-^6 or 0.000 000 000 000 001 one trillionth 10-^15 or 0.000 000 001 one millionth 10-^9 or 0.000 000 001 one quadrillionth 10-^18 or 0.000 000 000