This would be an effective tool to use with students who already know how to add and subtract two-digit numbers. They should also have some basic knowledge of the hundreds and thousands place values before starting. For reinforcement, have students work in pairs using the Toolbox to practice making large numbers. Then they can apply what they practiced by playing the stamp game. As students get more confident with regrouping and carrying, have them use the bead frame and eventually the magic slate. It could be fun to incorporate the Playbox games into lessons as well, and have students share the silly monsters they create as they earn points.Continue reading Show less
Montessori Math: Add & Subtract Large Numbers is an interactive math tool that teaches students how to add and subtract three- and four-digit numbers by focusing on the concept of regrouping units. At the home screen, students tap the desired operation icon to choose either addition or subtraction, then choose the stamp game, the bead frame, or the magic slate. The stamp game and the bead frame use place-value decomposition to help students practice regrouping and carrying when they add or subtract large numbers, and the magic slate offers them the opportunity to work in columns, one digit at a time. When students return to the home screen, they can access a Toolbox and a Playbox. In the Toolbox, they practice using the stamps and bead frame to make numbers. In the Playbox, they apply what they've learned -- as well as take on more challenging problems -- by playing three different games. In "Missing Digits," kids have to find missing digits in addition and subtraction problems. In "Wiz Quiz," they get timed, random problems to solve. And in the "Bubble Game," they drag the correct bubbles into place to complete problems. Students earn points, which they can use in the Monster Lab to buy body parts and build a silly monster. Other features of the app include the ability to add multiple user profiles and customize settings, including choosing a language, turning off the sound, and setting parameters on the numbers used in the math problems.
Students should at least be able to read two-digit numbers prior to using Montessori Math: Add & Subtract Large Numbers. In the stamp game, students break numbers into place values using "stamps" arranged in columns, and then either add or take away stamps to get the sum or difference. This approach helps them understand the concept of regrouping and carrying, as does the Toolbox activity in which they practice decomposing numbers using stamps. When students use the bead frame, they continue to work on regrouping and carrying, but they have to carry over more often because there are fewer pieces for each place value. When students use the magic slate, they apply the more traditional approach of working in columns. The learning progression is excellent and can be customized to fit different levels. Students don't have to complete one area of instruction in order to use the next one, so they can start anywhere they like and move among different areas as needed.
Key Standards Supported
Number And Operations In Base Ten
Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:
Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three- digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
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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