MegaPro Calculator 5000 by Chris Ternoey is a powerhouse of mathematical understanding. Addition and subtraction with regrouping are two of the most difficult concepts to teach. Combining a working knowledge of Base 10 with the procedures needed to correctly solve the problems can be overwhelming for many students. Teachers have struggled to find an easy way to introduce these concepts. This app has uncovered the secret!

After spending some time learning about Maria Montessori’s methods, Chris decided the calculator needed to be upgraded. He says, “A lot of teachers want children to use calculators early and often so they can explore mathematics beyond simple arithmetic. Others are concerned that children will not develop number sense if they work with calculators too much. I think both sides can be happy if we just reimagine how student calculators should behave.” Reimagine is what Chris has done. MegaPro has taken mundane numerical **calculations** and turned them into engaging numerical **interactions**.

Students can use the app to solve both addition and subtraction problems. Entering the app, the user is given two choices. First, the app can be used as a calculator. Additionally, the app has the ability to create random problems for students to solve. As a teacher, practicing procedures **correctly**, repeatedly is often the key to success. Research tells us that many students need exposure to new information over 100 times before they can process new material. This app provides opportunities for repeated practice in spades. What’s better is that the app directs student learning leaving little room for error, putting emphasis on **correct **learning.

Each problem is displayed in the center of the screen. Digits are represented by both manipulatives and numerals. The top digits are always green and represented by groups of balls while the bottom digits are blue and represented with cubes. As the student progresses through each step in solving the problem in the center of the screen, the upper left corner of the screen simultaneously shows what each step will look like on a piece of paper, providing support for students learning the procedures.

## To add:

- Drag the top digit over the bottom digit. The app will automatically combine the manipulatives and add the digits together.

2. If the total needs to be regrouped into the adjoining column, drag the tens into the tens column.

3. Then drag each digit in the tens column down. The app will combine each ten and place the correct sum in the proper location.

## To Subtract:

- If there needs to be regrouping (borrowing), drag the digit in the tens place over to the ones,

2. Drag the digits in the one’s column down to subtract the numbers.

3. Drag the digits in the tens column down to subtract numbers and find the difference.

MegaPro Calculator is a great tool to add to any teacher’s or parent’s arsenal. TWA recommends this app for its high quality, ease of use, and educational value. Don’t miss out on this revolutionary, out-of-the-box calculator! And watch out for Chris Ternoey! This emerging app developer shows promise and while this may be his first app on the market, it will most definitely not be his last!

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