Grade 4 · Unit 1: Number and place value

Written addition

Column addition with 4- and 5-digit numbers.

Harvest totals

A village harvested 4785 kg of rice in Aman season and 3648 kg in Boro season. How much altogether? Estimate first: 5000 + 4000 = 9000.

Column method

Ones: 5 + 8 = 13. Write 3, carry 1. Tens: 8 + 4 + 1 = 13. Write 3, carry 1. Hundreds: 7 + 6 + 1 = 14. Write 4, carry 1. Thousands: 4 + 3 + 1 = 8. Total: 8433 kg.

Adding more than two numbers

When numbers have different lengths, line up the ones. 2405 + 1386 + 975: add each column. The answer is 4766.

Check

Our answer is close to the estimate. Subtract to check: 8433 − 3648 = 4785. Two checks make us confident.

What I learnt

• I can add 4- and 5-digit numbers in columns.
• I can add three numbers.
• I can check with estimates and inverses.