Question

1.4 – 5.5 – 1.73 + 1.8 – 1.09 –5.12 –8.72 5.12 –1.66

Answer 1

We'll do two by two,
1.4 – 5.5= -4.1
– 1.73 + 1.8= 0.07
Leaving – 1.09,

You get  
=-4.1+ 0.07- 1.09
=-4.03-1.09
=-5.12