## Key Concepts

- Organize data into categories.
- Define a tally mark.

**Numbers**

We can count the number of items using our hands.

**Addition of numbers**

We can add numbers to find the sum of two or more objects.**Example:**Mother gave 4 chocolates to Alex. Later, his grandfather gave 5 chocolates to Alex. How many chocolates does he have in total?

Therefore, Alex had 9 chocolates in total.

**Subtraction of numbers**

To find the difference between two numbers/quantities, we subtract the smaller value from the larger value.

**Example: **You have 8 balloons. Your friend borrows 2 balloons. How many balloons do you have now?

Number of balloons left = Total number of balloons – Number of balloons your friend borrowed

= 8 – 2

= 6

**Organize Data**

- We can organize data by counting the number of items present/required.
**Example:**For the given data, find the number of each pet.

We can arrange the number of pets in a table by counting the number.

**Tally marks**

- The hash marks used to collect/organize data are called
**tally marks**.

- One vertical line is drawn for each of the first four numbers. [1, 2, 3, 4]

- The fifth number is represented by a diagonal line across the previous four.

- Count the tally marks by 5s.

**Tally table**

- We can represent the data in a tally chart.

**Example:** Barry observed the following insects in his garden. What is the number of bugs, spiders, bees?

**Insects**

- We can represent the data in table.

## Exercise

- There are several birds in the cage. Observe the list of birds in the cage and answer the following:

a. Make tally marks for the number of parrots in the cage?

b. What is the total number of birds in the cage?

c. Find the bird with least count.

2. Observe the list of vegetables and answer the following:

a. Find the number of cabbages.

b. Which vegetable is in the highest quantity?

### Concept Map:

- One vertical line is drawn for each of the first four numbers. [1, 2, 3, 4]
- The fifth number is represented by a diagonal line across the previous four.

### What we have learned

The hash marks used to collect/organize data are called tally marks.

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