Salutations!
To round to the nearest tenth, you need know whether the number next to tenth place is greater than 5 or lesser than 5. If its greater than 5, you need to round up. If its lesser than 5, you need to round down. Now, in the number 26.99 9 is in the tenth place. The number next to 9 is greater than 5, so just add on to the ones place, making the tenth and hundredth place 0. Zero has no value so whether you add the zero or not, it does not matter.
26.99 round to the nearest tenth ≈ 27
Hope I helped (:
Have a great day!