https://www.khanacademy.org/math/ncert-math-class-9-new/x56891bfac37feca0:the-world-of-numbers/x56891bfac37feca0:integers-expanding-the-horizon/v/history-of-numbers 2026-05-08T11:30:41.151510948Z History of numbers Discover the evolution of counting, from early survival methods like body-part pointing and prehistoric tally marks on bones to the grouping systems of indigenous cultures. The video follows the development of structured symbols like Roman numerals and the ultimate breakthrough in ancient India: the base-10 system and the invention of zero. Learn how these Hindu-Arabic numerals traveled through the Arab world to Europe, eventually becoming the global standard for modern mathematics Timestamps: 00:00 - Need for counting 00:42 - Method 1: using physical objects 01:02 - Method 2: using standard names 01:22 - Method 3: using written symbols 02:12 - Yajurveda Samhita 02:46 - Bakhshali manuscript 03:04 - How numbers travelled? 04:10 - Early number systems 04:44 - Tally marks 05:58 - Group of 2's Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw History of numbers Discover the evolution of counting, from early survival methods like body-part pointing and prehistoric tally marks on bones to the grouping systems of indigenous cultures. The video follows the development of structured symbols like Roman numerals and the ultimate breakthrough in ancient India: the base-10 system and the invention of zero. Learn how these Hindu-Arabic numerals traveled through the Arab world to Europe, eventually becoming the global standard for modern mathematics Timestamps: 00:00 - Need for counting 00:42 - Method 1: using physical objects 01:02 - Method 2: using standard names 01:22 - Method 3: using written symbols 02:12 - Yajurveda Samhita 02:46 - Bakhshali manuscript 03:04 - How numbers travelled? 04:10 - Early number systems 04:44 - Tally marks 05:58 - Group of 2's https://cdn.kastatic.org/ka-youtube-converted/1t2QlYjCJTU.mp4/1t2QlYjCJTU.mp4 449 Integers: Expanding the Horizon https://www.khanacademy.org/math/ka-math-class-7/x26f4f4b84655c15c:integers-ncert-new-indian-accent/x26f4f4b84655c15c:properties-of-addition-and-subtraction-of-integers-indian-accent/v/closure-property-for-additionsubtraction-integers 2024-03-14T20:05:09.2926958Z Closure Property for Addition/Subtraction for Integers This video discusses what is Closure property for addition and subtraction for integers. Devashish Phadnis video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Closure Property for Addition/Subtraction for Integers This video discusses what is Closure property for addition and subtraction for integers. https://cdn.kastatic.org/ka-youtube-converted/uWC47BRML1c.mp4/uWC47BRML1c.mp4 336 Integers: Expanding the Horizon https://www.khanacademy.org/math/ka-math-class-7/x26f4f4b84655c15c:integers-ncert-new-indian-accent/x26f4f4b84655c15c:properties-of-addition-and-subtraction-of-integers-indian-accent/v/what-is-additive-identity 2024-08-02T14:34:16.112060016Z What is additive identity In this video we cover what is additive identity and what is the significance of studying this thing ? Learn about this in a simplest way possible. Devashish Phadnis video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw What is additive identity In this video we cover what is additive identity and what is the significance of studying this thing ? Learn about this in a simplest way possible. https://cdn.kastatic.org/ka-youtube-converted/LBnYQwbjwHc.mp4/LBnYQwbjwHc.mp4 186 Integers: Expanding the Horizon https://www.khanacademy.org/math/tg-math-class-7-bridge/x2648a6cb9a4fb7d5:numbers-and-properties/x2648a6cb9a4fb7d5:properties-of-whole-numbers/e/additive-and-multiplicative-identity 2026-01-16T09:40:42.440263577Z Additive and Multiplicative identity In this exercise, we will learn that, for whole numbers, zero is the additive identity, and one is the multiplicative identity. Khan Academy exercise https://www.khanacademy.org/math/class-7-ncf/x063f95a40c290960:operation-with-integers/x063f95a40c290960:multiplication-of-integers/v/multiplying-positive-negative-numbers-india 2025-03-28T07:05:36.573142233Z Multiplying positive & negative numbers Multiplying positive & negative numbers (Indian Accent) Aakash Bagga video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Multiplying positive & negative numbers Multiplying positive & negative numbers (Indian Accent) https://cdn.kastatic.org/ka-youtube-converted/0OCU0QBrcw0.mp4/0OCU0QBrcw0.mp4 309 Integers: Expanding the Horizon https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-negative-numbers-multiply-and-divide/cc-7th-mult-div-negatives/e/multiplying_and_dividing_negative_numbers 2026-06-25T15:20:43.867868178Z Multiplying negative numbers Practice multiplying single-digit integers. Jason Persampieri exercise