Adding / Subtracting

In grade 4, students are not required to use the standard algorithm to add or subtract decimals. That is, they do not have to vertically add them by lining up the decimals.

Since they just deal with tenths in this grade, this means the key operational sense understanding is to fully comprehend that it takes ten tenths to make a whole.

This is one of the essential understandings of decimals: unitizing. This just means that in our place value system, you need ten smaller pieces to make one larger unit to the left, or each larger unit is made of 10 smaller units.

Decimal Blackjack

This game is a great way for students to add decimals to tenths informally.  It continually reinforces that once you get ten tenths, you make a whole. The basic set of cards is included in this file.

Blackjack cards with visual

This set of cards has a visual representation on them.  While some students or classes may require these to start, moving fairly quickly to the numbers only deck helps move students to the abstract level.

 

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