Ctrl+k

Find missing addends

A missing addend is the unknown part in a whole-number addition equation, such as a+□=ba+\square=b or □+a=b\square+a=b; it can be determined by interpreting the total and known addend as part–whole quantities and finding their difference. Understanding the inverse relationship between addition and subtraction supports efficient reasoning with multi-digit numbers, place value, and bar-model or equation representations, without extending here to fractional, decimal, or general algebraic unknowns.

Detailed Explanation: Find missing addends

A missing addend is the number that completes the total. To find it, subtract the known addend from the total:

missing addend=total−known addend\text{missing addend}=\text{total}-\text{known addend}

Example:

347+□=912347+\square=912
  1. The total is 912912, and the known addend is 347347.
  2. Subtract the known addend from the total:
912−347=565912-347=565
  1. The missing addend is 565565.
  2. Check by adding:
347+565=912347+565=912

So,

347+565=912\boxed{347+565=912}

Learn by doing: Find missing addends

Click a topic below to practice the foundational skills you'll need, learn the steps, or master this skill

    Practice with unlimited practice problems

    Place Value - Missing a Place

      ?