Four-Addend Sums

Four-Addend Sums

When you add four whole numbers, the answer stays the same no matter how you group the numbers. That means you can choose an order that makes the work easier.

1) Look for easy pairs

Start by spotting numbers that make a friendly total, such as:

• two numbers that add to 10,
• two even numbers,
• a pair that gives a round ten or hundred.

2) Group for efficiency

Instead of adding from left to right, combine the numbers in a helpful way. For example, if two addends make a convenient sum, calculate that first, then add the remaining numbers.

3) Add the partial sums

Once you have an easier intermediate total, finish by adding what is left. Keep the work neat so you can follow each step.

4) Check your result

A quick check is to estimate. If all four numbers are whole numbers, think about whether the final total should be near your mental estimate. You can also add again in a different grouping to see if you get the same answer.

Example strategy

• Find a pair that makes 10.
• Add the other two numbers.
• Combine the two partial sums.

Choosing an efficient order saves time and reduces mistakes.