How to simplify and how to calculate 2.8×13+3.6×4.5 = = 23.4÷7.8×2.1 = =

How to simplify and how to calculate 2.8×13+3.6×4.5 = = 23.4÷7.8×2.1 = =

2.8×13+3.6×4.5
=36.4+162
=198.4
23.4÷7.8×2.1
=3×2.1
=6.3