Order
of Operations is one concept in the
traditional mathematics curriculum that programmers quickly forget. You will
never see code written to evaluate expressions like this, 42 - 6 x 2 ÷ 4 x 3 + 5.
So, how are operations handled in Scratch?
Look at the green Operators menu in Scratch.
Note that the four arithmetic operators, the random number picker, string
operators (join, letter, length), mod,
round, and square root operators are rounded at each end. The relational (<. =, >) and Boolean
operators (and, or, not) are pointed at
each end.
The rounded ends represents parenthesis.
Will this block evaluate as 9 or 7?
If you look carefully you will see that the parenthesis tell us that the block will evaluate as 7.
To build the expression, drop the
multiplication block into the addition block. The white circle can be thought
of as a set of parenthesis ( ).
If you build the expression and then
click on it, it will report 7.
Order of operations are very simple in Scratch.
Think parenthesis!