You follow the Order of Operations:
P - parenthesis
E - exponents
M - multiplication
D - division
A - addition
S - subtraction
Take #3 for example:
10-18÷3+1
No parenthesis, no exponents, no multiplication, but there's division! -18÷3, which equals -6.
So, now the newly written equation is:
10-6+1
Next, there's addition. -6+1, which equals -5.
Newly written equation:
10-5
Finally, there's subtraction.
10-5=5
So, the answer is 5.
