Question

to find 19+(11+37), lennie added 19 and 11. then he added 37 to the sum. what property did he use?

Answer 1

Lennie used associative law of addition.
Associative law of addition doesn’t matter how you group the given numbers to add.

a + (b + c) = (a + b) + c
=> 19 + (11 + 37) or ( 19 + 11) + 37
=>  19 + (48) or (30) + 37
=> 67 or 67