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FF.1 Add or subtract using break apart - up to three-digit numbers

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What are mixed operations?

Mixed operations mean solving problems that use both addition and subtraction. In second grade, we use numbers up to three digits (hundreds, tens, and ones). To make solving easier, we can use a strategy called break apart.

Examples:
  • 245 + 36
  • 327 − 48
  • 412 + 25 − 13
Note

Mixed operations require careful attention to the signs (+ or −). Always read the problem slowly to see if you are adding or subtracting.

How to solve using break apart

The break apart strategy means separating a smaller number into tens and ones (or hundreds, tens, and ones) so the problem is easier to solve step by step.

Steps:
  • Take the smaller number in the problem.
  • Break it apart into place values (hundreds, tens, ones).
  • Add or subtract each part one at a time.
  • Combine the results to find the final answer.
Note

Breaking apart helps you work with friendlier numbers and reduces mistakes.

Examples of addition with break apart

Let’s add a 3-digit number and a 2-digit number by breaking apart the smaller number.

Example:
  • 245 + 36
  • Break apart 36 → 30 + 6
  • 245 + 30 = 275
  • 275 + 6 = 281
  • Answer: 281
Note

Always add the tens first, then the ones. It makes the problem easier to solve.

Examples of subtraction with break apart

We can subtract a 2-digit or 3-digit number by breaking it apart into tens and ones.

Example:
  • 327 − 48
  • Break apart 48 → 40 + 8
  • 327 − 40 = 287
  • 287 − 8 = 279
  • Answer: 279
Note

Subtract in steps: first tens, then ones. This keeps the numbers simple.

Mixed addition and subtraction

Sometimes problems have both addition and subtraction. Solve them one step at a time, breaking apart when needed.

Example:
  • 412 + 25 − 13
  • First, add: 412 + 25 = 437
  • Now subtract: 437 − 13
  • Break apart 13 → 10 + 3
  • 437 − 10 = 427
  • 427 − 3 = 424
  • Answer: 424
Note

Work left to right. Add first, then subtract, unless the directions tell you something different.