3.NBT.2. Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
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Not Right For WatchKnowLearn
Ages: 8  14
7581 Views:

When Diffy opens, there are four black numbers placed at the corners of a black square. Your first goal is to fill in the four blanks in the blue circles in the middle of each side of the black square.
Start with any side of the black square and cli...ck in the blank in the blue circle on that side and type in the difference of the black numbers on that side (the larger black number less the smaller one). So if the black numbers on the top side of the black square were 7 and 12, we would type 5 (= 12 – 7) in the blue circle between the 7 and the 12.
Note: There are more directions on the right side.
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May 9, 2010 at 11:11 AM


Not Right For WatchKnowLearn
Ages: 6  9
6933 Views:

Students will learn how to find the value of a digit by determining its place value. User clicks through the two slides.
May 20, 2010 at 02:23 PM


Not Right For WatchKnowLearn
Ages: 6  10
5292 Views:

In this computer animated video, students are shown how to read money amounts with decimals. Next, they are shown stepbystep how to add with decimals. Then, they are shown strategies for solving word problems using addition or subtraction.
November 28, 2010 at 06:50 PM


Not Right For WatchKnowLearn
Ages: 7  12
5573 Views:

For estimating sums and differences of whole numbers, try out these two strategies: rounding and frontend estimation. Learn more about estimation with this stepbystep, interactive video from StudyJams. A short, selfchecking quiz is also includ...ed with this link.
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June 10, 2011 at 05:40 PM


Not Right For WatchKnowLearn
Ages: 5  10
5148 Views:

Chip Abacus
From usu.edu, produced by Utah State University


With this manipulative, you can represent place value and exchanges in base 2, base 5, or base 10. Set the desired base with the up and down arrow buttons below the workspace. Chips in columns then represent units (1), bases (2, 5, or 10), and bases...quared (4, 25, or 100), as indicated by the numbers at the top of each column.
Note that chips can be dragged within a column but not from one column to another.
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May 9, 2010 at 10:40 AM


Not Right For WatchKnowLearn
Ages: 4  10
4703 Views:

This virtual manipulative abacus allows children to explore other representations of numbers. (It uses a Java applet).
May 9, 2010 at 09:54 AM


Not Right For WatchKnowLearn
Ages: 7  9
3853 Views:

This teachercreated video shows students how to identify key words in word problems which will tell them whether to add or subtract to solve the problem. " In all" means to add;" have left "means to subtract. Sample problems are written on chart pa...per. The teacher reads each problem and circles key words. (01:56)
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September 8, 2011 at 06:57 PM


Not Right For WatchKnowLearn
Ages: 7  11
1206 Views:

In this interactive game, students are shown addition/subtraction problems with missing numbers. They are shown three choices of numbers to use to complete each problem. The game contains three levels, with numbers ranging from one to three digits.... (This link is for an interactive game and may take a few minutes to load.)
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July 14, 2012 at 09:46 AM


Not Right For WatchKnowLearn
Ages: 7  12
4254 Views:

This video provides a brief demonstration of how to add twodigit numbers, using 12+19 as an example. (00:55)
March 25, 2009 at 12:09 PM


Not Right For WatchKnowLearn
Ages: 6  10
9227 Views:

Here's a fun game to help teach place value (ones, tens AND hundreds). You will need a 3 compartment dip tray and matching colored dice. Students play against each other. This is a great opportunity to review place value and even greater than/less th...an activities. (3:30)
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August 31, 2011 at 09:37 PM
