12+?+3−1=29 12+?+3-1=29 12+?+3−1=29
To find out which number is missing, we solve the entire exercise to know which number we will have to add to obtain a result of 29:
12+3−1= 12+3-1= 12+3−1=
15−1=14 15-1=14 15−1=14
To make 14 equal to 29, we will have to add 15.
Let's verify:
29−14=15 29-14=15 29−14=15
15 15 15