4th grade addition and subtraction

Example

51 533 + 425 137 = ?

1. 51 533 + 425 137 = 476 670

Answer: 476670

Example

438 155 + 205 790 = ?

1. ones: 5 + 0 = 5
2. tens: 5 + 9 = 14, carry 1
3. hundreds: 1 + 7 + 1 = 9
4. thousands: 8 + 5 = 13, carry 1
5. ten thousands: 3 + 0 + 1 = 4
6. hundred thousands: 4 + 2 = 6
7. 438 155 + 205 790 = 643 945

Answer: 643945

Example

872 157 − 488 992 = ?

1. ones: 7 − 2 = 5
2. tens: exchange, 15 − 9 = 6
3. hundreds: exchange, 10 − 9 = 1
4. thousands: exchange, 11 − 8 = 3
5. ten thousands: exchange, 16 − 8 = 8
6. hundred thousands: 7 − 4 = 3
7. 872 157 − 488 992 = 383 165

Answer: 383165

Example

Estimate 7242 − 3757 by rounding each number to the nearest thousand.

1. 7242 ≈ 7000, 3757 ≈ 4000
2. 7000 − 4000 = 3000

Answer: 3000

Example

A warehouse has 75 913 boxes. 7549 are sent out and 4766 new boxes arrive. How many boxes are there now?

1. 75 913 − 7549 = 68 364
2. 68 364 + 4766 = 73 130

Answer: 73130