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Extensions 
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Tab Resize - split screen layouts
Split Screen made easy. Resize the CURRENT tab and tabs to the RIGHT into layouts on separate windows. w/ Multi Monitor Support.
Split Screen for Google Chrome
You can easily split and separate tabs, split interface layout, and resize tabs by columns and rows. Multi-monitor support
Merge PDF - Split PDF - Sejda.com
Split, Merge or Convert PDF to JPG, Extract pages, Alternate scans and much more.
Alice Keeler Gradebook Split
Teachers, when grading digital work use this extension to bring up your gradebook side by side with the students work.
Split PDF | ilovepdf.com
Select a range of pages, separate one page, or convert each page of the document into independent PDF file.
Cloud Split Downloader (Download Accelerator)
It allows you to split-download a file into several chunks like download accelerator. Supports Google Drive, Dropbox, OneDrive.
PDF Merge and Split (Without Server)
It allows you to merge, split, remove, and rotate PDFs for free. This app only works locally without uploading PDFs to any server.
Alice Keeler Classroom Split
Have your students install this extension to allow students to have their Google Classroom directions side by side with their work