 "Green Blocks" redirects here. For Extension blocks, see Scratch Extensions.
Operators blocks is one of the ten categories of Scratch blocks. They are colorcoded lightgreen, and are used to script math equations and string handling. It was previously titled Numbers Blocks, but was renamed in Scratch 1.4 due to new blocks that handled strings.
There are currently 18 Operators blocks: 7 Boolean blocks and 11 Reporter blocks. This and PicoBoard Blocks are the only categories to contain no Stack blocks.
Blocks
Note:  Click on a block to learn more about it. 
Scratch 3.0 has the following 7 Operators Boolean Blocks:
Scratch 3.0 has the following 11 Operator Reporter blocks:

(() + ())

(()  ())

(() * ())

(() / ())

(pick random (1) to (10))

(join [hello] [world])

(letter (1) of [world])

(length of [world])

(() mod ())

(round ())

([sqrt v] of (9))
Obsolete Blocks
Prior to Scratch 1.2, the () of () block was two separate blocks, Abs () and Sqrt (), with no other mathematical functions.
Suggestions
Scratchers have suggested an Operators block that solves exponents.^{[1]}^{[2]}
(() ^ ():: operators)
Some Scratchers have suggested true and false Booleans, however this has not been implemented, possibly due to the easy workaround.^{[3]} Here is a sample of what such blocks might look like:
<true::operators> <false::operators>
Instead, here is a workaround that is usually mentioned:^{[4]}
set [variable v] to [true] set [variable v] to [false]
References
() + () • ()  () • () * () • () / () • Pick Random () to () • () < () • () = () • () > () • () and () • () or () • Not () • Join ()() • Letter () of () • Length of () • () Mod () • Round () • () of ()More blocks...

Main Block Categories 
Motion Blocks • Looks Blocks • Sound Blocks • Events Blocks • Control Blocks • Sensing Blocks • Operators Blocks • Variables Blocks (List Blocks) • My Blocks 
Extensions 
Music Extension • Pen Extension • Video Sensing Extension • Text to Speech Extension • Translate Extension • Makey Makey Extension • micro:bit Extension • LEGO Mindstorms EV3 Extension • LEGO Education WeDo 2.0 Extension • Go Direct Force and Acceleration Extension • PicoBoard Extensions 