## Grouping and Grazing

Grade:

Pre-K-2

Standards:

Math Content:

Number and Operations

Help the alien spaceship move cows into corrals by counting, adding, and subtracting. This activity helps children learn grouping, tally marks, and place value. As they master counting, they can move on to adding and subtracting two-digit numbers.

**This interactive is optimized for your desktop and tablet.**

**General Tools**

**Select**allows you to select cows and drag them. Once a cow is selected, it will turn purple.**Group**corrals selected cows into groups of 5 or 10, depending on the activity.**Break Group**removes selected cows from a corral.**Check**allows you to input the correct final number of cows.**Subtract**allows you to subtract away all the selected cows.**New Set**button(s) will provide a new problem or allow you to create your own problem.

For every correct answer, you will receive a barn () at the top of the screen.

**Count by 5s**

- Count cows by corralling them into groups of 5. To do this, select cows until 5 are purple and upside down. Then, click
**Group**. Repeat this step until you can no longer group 5 cows together. Loose cows should be moved into the upper area separately using the**Select**tool. **Tally**counts cows as you group using tally marks. It may be hidden at any time using the arrow at the top of the Tally window.**New Set**displays a new problem at any point.**Check****Count with Me**counts cows by selecting first all groups of corralled cows and then all loose cows. The count will also be displayed in the Tally window, if shown.**Count Alone**lets users input the number of cows into a calculator. The count will also be displayed in the Tally window, if shown.

**Count by 10s**

- Count cows by corralling them into groups of 10. To do this, click on the cows until 10 are purple and upside down. Then, click
**Group**. Repeat this step until you can no longer group 10 cows together. Loose cows should be moved into the upper area separately using the**Move**tool. **New**displays a new problem at any point.**Check****Count with Me**counts cows by selecting first all groups of corralled cows and then all loose cows.**Count Alone**lets users input the number of cows into a calculator.

**Add**

- Begin by moving all cows from the bottom two areas up to the sum field to combine them. Then, group loose cows by 10s if there are enough loose cows. This is the same as carrying using the traditional addition method.
**Check**: After moving the cows into the sum field, press check to enter in the sum.**Any Numbers (double arrow)**displays a new problem at any point using numbers selected by the computer.**My Numbers****(settings wheel)**displays a new problem at any point using numbers you select. Value must be between 0 and 20.

**Subtract**

- Begin by selecting the number of cows that you want to
subtract. You may need to ungroup cows to remove the correct number.
This is the same as borrowing using the traditional subtraction method.
Then, press the
**Subtract**button. - Next, move the remaining cows to the difference field. Press
**Check**to enter the difference and complete the problem. **Any Numbers**displays a new problem at any point using numbers selected by the computer.**My Numbers**displays a new problem at any point using numbers you select. The value in the first box must be between 0 and 20. The value in the second box must be at least 0 but less than the value in the first box.

**Count**

- Before starting a problem, can you estimate how many groups you will have? Now, try it. Was your estimate correct? After doing the activity many times, does your estimate get better?
- Is it faster to count the total number of cows before you group them or after you group them?
- When counting by 10s, how does the written number relate to the final grouping of cows?

**Add**

- After trying a few addition problems, can you tell when you will need to group or ungroup cows?
- How is grouping cows in the addition activity similar to how you normally solve addition problems on paper?

**Subtract**

- After trying a few subtraction problems, can you tell when you will need to group or ungroup cows? How is this similar or different from the addition problems?
- How is ungrouping cows in the subtract activity similar to how you normally solve subtraction problems on paper?