Lila's error was that she added -7.13 to 63.97 to get -71.1
Lila steps are as folows
(−7.13 + 63.97) + (−54.8 − 3.4) = −71.1 + (−58.2) = −129.3
In the first bracket, Lila was suppose to subtract 7.31 from 63.97 since there is a negative in front of 7.31.
So, the correct expression should be
(−7.13 + 63.97) + (−54.8 − 3.4) = 56.84 + (−58.2) = 56.84 - 58.2 = −1.36
So, Lila's error was that she added -7.13 to 63.97 to get -71.1
Learn more about addition and subtraction here:
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