Respuesta :

Lets round 1st:-

26.73 = 26.7
89.42 = 89.4

Now lets add:-

26.7 + 89.4 = 116.1

CHECK OUR WORK:-

116.1 - 26.7 = 89.4 
We were RIGHT!!

Hope i helped ya!! 
easy do it just like this 26.70+89.40=126.1