The expression is 6.2 + 4.2 + 4.3 + 5.8. \ \

\

= 6.2 + 4.2 + 5.8 + 4.3                (Commutative Property: a + b = b + a)

= 6.2 + (4.2 + 5.8) + 4.3             (Associative Property: (a + b) + c = a + (b + c))

= 6.2 + 10 + 4.3                          (Add: 4.2 + 5.8 = 10) \ \

= 6.2 + 4.3 + 10                          (Commutative Property of Addition: a + b = b + a)

= (6.2 + 4.3) + 10                       (Associative Property: (a + b) + c = a + (b + c))

= 10.5 + 10                                (Add: 6.2 + 4.3 = 10.5)

= 20.5                                        (Add: 10.5 + 10 = 20.5)

The value of the expression is 20.5.