Asap im marking 70 + 2 + 0.3 + (-30) + (-9) + (-0.1) = 70 + (-30) + 2 + (-9) + 0.3 + (-0.1) in associative property

Left had side:

70 + 2 = 72
72 + 0.3 = 72.3
72.3 + -30 is the same as 72.3 - 30 = 42.3
42.3 + -9 is the same as 42.3 - 9 = 33.3
33.3 + -0.1 is the same as 33.3 - 0.1 = 33.2

Right hand side:

70 + -30 is the same as 70 - 30 = 40
40 + 2 = 42
42 + -9 is the same as 42 - 9 = 33
33 + 0.3 = 33.3
33.3 + -0.1 is the same as 33.3 - 0.1 = 33.2

Therefore:

33.2 = 33.2

Which is true

On monday,mrs.wise bought 3 lbs of apples at $4per lb= 4*3=$12on tuesday ,20%off and she buy 5 lbs of apples = $4-20%=3.20*5lb=$16example: other wise when she buy 5lbs on monday she have to spend 4*5=20

Wow. that is a really cool question.