2/9 (1.8 - 5.4 - 3/7 (2.1 - 4.2))= 2/9 (1.8 - 5.4 - 3/7 -2.1)= 2/9 (1.8 - 5.4 + 6/7 2.1)= 2/9 (1.8 - 5.4 + 1.8)= 2/9 (-2.6 + 1.8)= 2/9 * -0.8= -1.6/9= -0.17777777778.
2/9 (1.8 - 5.4 - 3/7 (2.1 - 4.2))
= 2/9 (1.8 - 5.4 - 3/7 -2.1)
= 2/9 (1.8 - 5.4 + 6/7 2.1)
= 2/9 (1.8 - 5.4 + 1.8)
= 2/9 (-2.6 + 1.8)
= 2/9 * -0.8
= -1.6/9
= -0.17777777778.