Double Century – Class 3 Maths Chapter 3 Notes & NCERT PDF

Introduction

Double Century takes children from numbers up to 100 to numbers up to 200. It opens with The Story of Our Numbers: tens of thousands of years ago people made marks on cave walls and tree bark to keep records, and later counted in groups of 5, 10, 20 and 60. Thousands of years ago, ancient Indians created a way to write any number, however large, with only ten symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. The book calls this one of the most creative inventions in human history, and says the symbol 0, meaning "nothing", is what really made the system work.

What's in this Chapter

1. Estimating and a number board. Children estimate oranges, bangles, laddoos, barfi, bindis and bananas, and fill missing numbers on a snakes-and-ladders board up to 100.

2. What is 100? The Talking Pot always says one more: say 42, Pot says 43; say 99, Pot says 100.

3. Making 100. Number sentences like 70 and 30 makes 100. Bholu makes 100 by jumping to 65 and then 35 more on a number line. Children make 100 with matchstick bundles and a ginladi (bead string), and fill flower petals that add up to 100.

4. Numbers beyond 100. "100 and 1 makes 101 (One Hundred One)", up to 110, then 123 as 1 hundred, 2 tens and 3 ones. Children place numbers on number lines up to 150.

5. Clap, Snap and Pat game. One clap = 100, one snap = 10, one pat = 1. Clap, snap-snap, pat-pat-pat = 123.

6. Counting to 200. 150 = "One hundred and fifty". The table continues to 200, and 200 is shown on a number line as 150 + 50 and 140 + 60.

7. Jumping game. Jumps of 5 and of 20 on number lines; 1 less and 1 more (1 less than 160 is 159, 1 more is 161).

Key Ideas

Activities from the Book

Words to Learn

Tips for Parents & Teachers

Common Mistakes