Solve for y: 23-12×(-5)+y÷7+[21-4]=107 Order of Operations Challenge

What is the number that should replace y?

$23-12\times(-5)+y\colon7+\lbrack21-4\rbrack=107$

We begin by solving the multiplication exercise:

$12\times(-5)=-60$

and subsequently the exercises within brackets:

$21-4=17$

We obtain the following:

$23-(-60)+y:7+17=107$

Keep in mind that a negative times a negative becomes a positive:

$23+60+y:7+17=107$

Next we simplify and add:

$23+60=83$

$83+17=100$

We obtain the following calculation:

$100+y:7=107$

We then rearrange the sections:

$y:7=107-100$

$\frac{y}{7}=7$

Lastly we multiply by 7:

$y=7\times7=49$