## Chapter 03 Double Century

### THE STORY OF OUR NUMBERS

Tens of thousands of years ago, people started counting. They wanted to keep records of their things. So they made marks on the walls of caves and on the barks of trees.

Over time, they kept records of their things by making groups of 5, 10, 20, and 60.

Thousands of years ago, the ancient Indians created a method for writing any number, however large, using only ten symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. It was one of the most ingenious and creative inventions in human history. It made possible the invention of TVs, computers, mobile phones, and more. This method of writing numbers is now used everywhere in every country in the world.

A very important part of this invention was the introduction and use of the symbol “0” to mean “nothing”. It is the number 0 that really made this system of writing numerals work!

Over the next few months, we will learn how to write all numbers, however large, using just these ten symbols.

#### Let us Do

**1.** Look at the picture. Estimate and write the number of each of the following objects.

a. Oranges : …………….

b. Bangles : …………….

c. Laddoos : …………….

d. Barfi : …………….

e. Bindis : …………….

f. Bananas : …………….

#### Let us Play

Fill the missing numbers on the board.

Answer the following on the basis of the Snakes and Ladders board:

**1.** Which number will you reach if you take the ladder from 13?
……………….

**2.** If you are on the snake at number 25, which number
will you reach? ……………….

**3.** You are standing on 96. Which number on the die will
take you to the snake’s mouth? ……………….

**4.** Show the number written on the tail of the longest snake using
bundles and loose sticks. ……………….

#### Let us Think

and one more makes 100. One more than 99 is 100.

10 bundles of 10 sticks each is 100 sticks

Oh, he scored a century. That is a 100 runs

10 Packets of 10 bindis each makes 100.

Teacher’s Note:Encourage children to represent numbers with matchsticks in the form of bundles and loose sticks.

#### Let us Do

**1.** Fill in the blanks.

Marking 100 | Number sentence |
---|---|

70 and 30 makes 100 | |

___ and ___ makes 100 | |

___ and ___ makes 100 |

Bholu made 100 by jumping on 65 and then 35 more

Make 100 by different jumps on this number line.

**2.** Use matchstick bundles and a ginladi to make 100 in different
ways. Fill the table below.

$ \begin{array}{|l|l|} \hline \text{60 and 40 makes …………..} & \text{45 and …………. makes 100.}\\ \hline \text{…………. and 25 makes 100.} & \text{…………. and 85 makes 100.}\\ \hline \text{…………. and …………. makes 100.} & \text{…………. and …………. makes 100.}\\ \hline \end{array} $

**3.** Write numbers in the blank space inside the flower petals so that the numbers in each petal add up to 100.

#### Let us Explore

**How many are 100?**

**1.** Open a full box of matchsticks.

• Estimate the number of matchsticks in the box: ………..

• Count the number of matchsticks in the box: …………..

• How close was your estimate?

• How many boxes of matchsticks will get the total close to 100 matchsticks? …………. boxes.

**2.** Take a handful of seeds like kidney beans, chickpeas, etc.

• Estimate the number of seeds you have in your hand: …………..

• Count the number of seeds in your hand: ………….

• How many handfuls of seeds will get the total close to 100 seeds? …………. handfuls.

Let’s observe the table and learn to write numbers beyond 100. Fill in the blank spaces.

100 and 1 makes One Hundred One | 101 | |

100 and 2 makes One Hundred Two | 102 | |

100 and 3 makes One Hundred ……….. | 103 | |

100 and 4 makes One Hundred ………. | 104 | |

100 and 5 makes One Hundred Five | …… | |

100 and 6 makes One Hundred………. | 106 | |

100 and 7 makes One Hundred Seven | …… | |

100 and 8 makes One Hundred ………. | 108 | |

100 and 9 makes One Hundred ………. | …… | |

100 and 10 makes One Hundred Ten | 110 |

#### Let us Do

**1.** Let’s continue making numbers above 100 using matchstick bundles and loose sticks.

In the table given below, identify the bundles and loose sticks and write the corresponding numbers.

Extend this table in your notebook till 150. Do you observe something common in all the numbers?

Match the numbers with the correct bundles and loose sticks.

Oh! Talking Pot is back. It will say one more than whatever you say

Fill the blank spaces on the number line.

Show the following numbers on the number line below.

**1.** Place an arrow on 125.

**2.** Make a tree on 112.

**3.** Make a smiley on 149.

**4.** Put a cross $\textcircled{\times}$ on 137

#### Let us Play

One clap represents 100 One snap represents 10 One pat represents 1

Two claps represent 200 Two snaps represent 20 Two pats represent 2

Play this game in two teams. One team will show a number using clap, snap and pat and the other team will guess it. Example: Clap – Snap Snap – Pat Pat Pat means 123 (One hundred and twenty three)

Let’s now count beyond 150.

#### Let us Do at Home

**1.** Fill a small container like a small bowl with seeds
such as kidney beans, chickpeas, etc.

**2.** Look closely at the container to estimate how many seeds are in it. Your Estimate: ……… seeds.

**3.** Now count and see how close your estimation is to the actual number of seeds. Counted ……… seeds.

**4.** Guess how many times you need to fill container to get close to 200 seeds? Your guess: ………. times.

$$ \begin{array}{|l|} \hline \text{I can show}\\ \text{200 on the }\\ \text{number line too. }\\ 150 + 50 = 200 \\ 140 +60 = 200 \\ \hline \end{array} $$

#### Let us Do

**1.** Draw jumps of 5 on the number line and write the numbers on the number line in the given spaces.

**2.** Continue jumps of 20 and write the missing numbers on the given number line.

**3.** Fill in the table.

1 less | Number | 1 more |
---|---|---|

160 | ||

129 | ||

187 | ||

134 | ||

158 |

**4.** Show at least two different ways of making the following numbers.

a. Use matchstick bundles to make 125.

b. Make 145 using a *ginladi*.

c. Make 170 on a number line

**5.** Fill in the empty boxes appropriately

**6.** Mark the following numbers on the number line.

a. 109, 112, 124, 134, 146

b. 155, 163, 178, 189, 198

c. 125, 142, 153, 174, 199