Answer:
_<u>7</u> + 3 = 3 + 7 : commutative property,[if something is added or subtracted]
0 +<u>5</u> _ = 5 is it: identity property.[if 0 is added or subtracted]
2 + (6 + 8) =(2 + 6)+ _<u>8</u> associated property
[if added or multiplied]
1.
15 × 12× 20
3600
2.
2×2×3
12
3.
24.3×8.5×9.7
2003.535