FILL • CHECK • FIND THE PATTERN
20×20 multiplication grid
Fill and check a 20x20 multiplication chart with 400 product cells. Work through one region at a time, compare mirrored facts, and use square numbers to connect multiplication with area.
20×20 multiplication grid
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Scroll sideways to see more columns
1 practice page + 1 answer page · 2 total · Letter · landscape
Connect the diagonal to area
The highlighted diagonal runs from 1 × 1 = 1 to 20 × 20 = 400. Imagine each fact as the area of a square. Compare 19² = 361 and 20² = 400: increasing both sides by one adds 39 unit squares.
Work through four regions
Begin with rows and columns 1–10. Next try rows 11–20 against columns 1–10, then their mirrored region. Finish the bottom-right region by splitting a factor: 17 × 14 = 10 × 14 + 7 × 14 = 238.
Practice with the 20×20 grid
The square-number diagonal highlights cells with equal factors, such as 4 × 4 = 16. Other cells can also contain square numbers, such as 2 × 8 = 16.
Enter a product in any cell and choose “Check answers.” The message counts correct answers, entries to try again, and empty cells. Individual checked cells have text labels for their result as well as color. Use the arrow keys to move between cells, or Tab to follow the form.
Do I need to fill every cell before checking?
No. Check one fact, one row, or a region whenever you like. Empty cells stay empty and are counted separately. “Clear grid” removes your entries so you can start again.
How is this different from the 1–20 reference chart?
This grid starts empty and lets you type and check products. The 1–20 multiplication chart starts filled for looking up facts and also offers printable blank and missing-number versions.
What is included in the landscape PDF?
The fixed download contains a blank grid and a separate answer key. “Download custom PDF” uses the current settings and entries. The custom PDF contains the 20×20 product grid with factors 1 through 20, any numeric entries you have made, and an optional separate filled answer key. The diagonal highlight carries over when selected. Both Letter and A4 use landscape pages.
Does 20×20 include zero?
No. It means 20 data rows and 20 data columns, using factors 1–20, plus headers. Adding zero through 20 would make 21 data rows and columns; that is not the grid shown here.
Are entries saved when I leave?
No. Entries stay in this page while you work. Download or print a copy to keep your progress; leaving or reloading the page resets the grid.