Developing Strategies for Addition and Subtracting Computation
1 iPad Apps
Mathboard- (The addition part of this app is free but to add subtraction, multiplication, division, etc. you must buy the full version.) This is an interactive chalkboard that gives a student a problem and then they must solve it. They have a space below the problem to work it out or an optional pull-out chart to help them solve the problem.
Arithmetic- This app can be used for addition and subtraction. Children must drag the fish to the correct answer and you questions get harder as you get more correct.
Math Zombies- Students use knowledge of math facts to answer problems to defend themselves against math zombies. The app can be set to different difficulty levels when you purchase the full version based on student progress.
2 Virtual Manipulatives
This website lists all the skills needed for second graders. Each practice gives you a preview of the problems before you select it. This is a great way for students to practice subtraction facts in many different forms. Ex- Subtracting 10. 80-60=__. 91-9=__.
Base Blocks Addition http://nlvm.usu.edu/en/nav/frames_asid_154_g_2_t_1.html
Base Blocks Subtraction http://nlvm.usu.edu/en/nav/frames_asid_155_g_2_t_1.html
“These two similar applets use base-ten blocks on a place-value chart. You can form any problem you wish up to four digits. The subtraction model shows the bottom number in red instead of blue. When the top blocks are dragged onto the red blocks, they disappear. Although you can begin in any column, the model forces a regrouping strategy as well as a take-away model for subtraction. Good for reinforcing the standard algorithms.”
(Page 26-27 in Math book)
Two-digit Addition and Subtraction
This website provides games that allow students to practice addition and subtraction using two-digit numbers. The game can be set to different levels to help ease them into the practice. It also encourages students to think on their feet and become more skilled with using two-digit numbers.
Key Standards Supported
Number And Operations In Base Ten
The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).
Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
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.
Operations And Algebraic Thinking
Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.1