Chapter 4 — We the Travellers — II

Chapter 4 of the Class 5 Mathematics NCERT textbook (Maths Mela), "We the Travellers — II", covers addition and subtraction of numbers up to five digits using place value — download the PDF and read a summary of topics including fuel arithmetic, consecutive number patterns, quick sum methods, even and odd numbers, and real-world problems involving travel distances and money.

• Addition and Subtraction Using Place Value — The chapter teaches multi-digit addition and subtraction by aligning digits in Ones, Tens, Hundreds, Thousands, and Ten-Thousands columns and regrouping when needed. Problems use real contexts such as a lorry carrying 28 and 75 litres of fuel, and India's North-South Corridor (1,855 km + 1,862 km = 3,717 km).
• Consecutive Number Patterns — Students explore sums of 2, 3, 4, and 5 consecutive numbers and observe whether the sums are even or odd and what the fixed difference between successive sums is. The pattern is then used to find sums like 67 + 68 + 69 without adding each number directly.
• Quick Sum and Difference Strategies — The chapter introduces a method to find the number that must be added to reach round targets such as 100, 1,000, or 10,000, and a quick way to subtract 9 or 99 from any number. Students learn to apply these strategies to solve problems mentally.
• Even and Odd Numbers — Students identify even and odd numbers and investigate what happens when two even numbers, two odd numbers, or one of each are added together, using paired arrangements to explain the pattern.
• Making Groups of Numbers with Equal Sums — The opening activity asks students to swap pairs of numbers between two groups so that both groups have the same sum, using the fewest possible moves — building number sense and strategic thinking.

1. 01Addition and subtraction of numbers up to five digits (TTh, Th, H, T, O) is practised by aligning digits and regrouping.
2. 02The India North-South Corridor problem (Srinagar to Kanniyakumari, 3,717 km in 2019) and sea route problems (Mumbai to Chennai, 2,700 km) provide real travel contexts.
3. 03Consecutive numbers are defined as numbers that follow one another without skipping; sums of 2, 3, and 4 consecutive numbers each show a fixed difference between successive totals.
4. 04A quick method to reach 100 or 1,000 is demonstrated: adjust the complement by 1 (e.g., 32 + 67 = 99, so 32 + 68 = 100).
5. 05Palindrome numbers — numbers that read the same forwards and backwards (e.g., 363, 8,558) — are introduced as an exploratory thinking activity.
6. 06Even and odd number rules for addition are discovered through paired arrangements: even + even = even, odd + odd = even, odd + even = odd.
7. 07Word problems involve money (Mary's train journey starting with Rs 12,540; Ambrish buying cows, goats, and a milking machine for Rs 92,375) and weight (a truck carrying 8,250 kg of goods).