very simple
part 1: 0.65 + 0.40 + 0.35 - 0.10
example of what you can do for part 2 (i want you to do some of the work so you learn :)
Example: Simplify 7.4 + 8.2 − 3.2 − 2.4 using the commutative and associative properties.
Step Expression Explanation
0 7.4 + 8.2 − 3.2 − 2.4 Original expression
1 7.4 + 8.2 + (−3.2) + (−2.4) Rewrite the subtraction using the additive inverse.
2 7.4 + (−2.4) + 8.2 + (−3.2) Use the commutative property to group similar numbers together.
3 (7.4 + (−2.4)) + 8.2 + (−3.2) Use the associative property to group the first pair of numbers.
4 5 + 8.2 + (−3.2) Simplify.
5 5 + (8.2 + (−3.2))
Use the associative property to group the last pair of numbers.
6 5 + 5 Simplify.
7 10