Question

Write the missing number to make the equation true. (5+_)+35= 5 + (12+ 35)

Answer 1

Data:
missing number = x

Solving:
$(5+x)+35= 5 + (12+ 35)$
$5+x+35= 5 + 47$
Put the numbers with incognito on the left and change the signal when changing sides if necessary, put the numbers without incognito on the right by changing the signal if necessary.
$x= \diagup\!\!\!\!5 + 47-\diagup\!\!\!\!5-35$
$x = 47 - 35$
$\boxed{x = 12}$

Replace found value and Confirm that the solution is correct:

$(5+x)+35= 5 + (12+ 35)$
$(5+12)+35= 5 + (12+ 35)$
$17+35= 5 + 47$
$\boxed{52=52}(TRUE)$

Answer:
The missing number to make the equation true is $\boxed{12}$

Answer 2

The answer is 12 because you are using the commutative property.