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Kindergarten · K.OA.A.5

Addition within 5 in kindergarten

Addition within 5 means adding small numbers with a total of 5 or less, such as 2+3=52 + 3 = 5. By the end of kindergarten, your child should know these sums quickly, along with subtraction within 5, without counting each time.

What the standard says

The official Common Core wording, quoted exactly. The plain version follows.

K.OA.A.5 Fluently add and subtract within 5.

What it means, in plain words

The goal for addition within 5 in kindergarten is fluency. Fluent means quick and correct, the way an adult answers 2+22 + 2 without thinking. Your child gets there by the end of the year. Early in kindergarten, counting on fingers is a normal step.

Within 5 there are only a few facts, and children learn them by seeing small groups: the dots on a die, the fingers on one hand. A child who sees 4 fingers and 1 finger as one full hand knows 4+1=54 + 1 = 5 without counting.

Subtraction within 5 uses the same facts turned around. If 1+4=51 + 4 = 5, then 5−4=15 - 4 = 1 and 5−1=45 - 1 = 4. Zero has its own simple rule: adding or taking away 0 leaves a number the same.

Your child should be able to:

  • Add two numbers with a total of 5 or less without counting each one
  • Subtract from 5 or less, such as 4−2=24 - 2 = 2
  • Say what happens when you add or take away 0
  • Show a fact with fingers or objects, such as one full hand for 5

Example

There are 2 red blocks and 3 blue blocks on the table. How many blocks are there in all?

  1. Your child may count every block: 1, 2, 3, 4, 5.
  2. A faster way is to know the fact 2+3=52 + 3 = 5.
  3. There are 5 blocks in all.

Example

You have 4 crackers and eat 1. How many crackers are left?

  1. Start with 4 crackers.
  2. Take 1 away and count what is left: 1, 2, 3.
  3. 4−1=34 - 1 = 3, so 3 crackers are left.

Where children usually get stuck

  • For 4+14 + 1, your child counts out 4 fingers, then 1 finger, then counts all 5 from the start, every time.

    The child has not yet seen 4 and 1 together as one hand, so each sum gets built from scratch.

    What helps. Show 4 fingers and ask how many more make a whole hand. Switch numbers and hands for a few minutes a day.

  • Your child writes 2+0=32 + 0 = 3.

    Adding feels like it should always make a number bigger, so the child adds 1 anyway.

    What helps. Act it out. Put 2 grapes on a plate, add no grapes and ask how many are on the plate now.

  • For 5−15 - 1, your child answers 6.

    Adding was learned first, so the child sees two numbers and adds them without reading the minus sign.

    What helps. Read the sign out loud together before solving: "five take away one". Then take 1 away from 5 real objects.

Try four practice questions

Real kindergarten questions from our question bank, easiest first. Answer them right here, check each one, and see a worked solution for any question.

  1. 1Warm-up
    James solved a subtraction problem. His work is shown below.
    3−0=3\displaystyle 3 - 0 = 3
    Choose the statement that best describes James's answer.
    A
    James's answer is right.
    B
    James's answer is one less than it should be.
    C
    James's answer is one more than it should be.
    D
    James's answer is much different from what it should be.
    Show the answer and how to solve it

    James's answer is right: 3 minus 0 is 3.

    1. 1Look at James's work.
    2. 2Find the right answer to 3 minus 0.
    3. 3James wrote 3, and 3 minus 0 really is 3. So James's answer is right.
    4. 4The right choice is the one that says James's answer is right.

    Common mistake. A common mistake is thinking James got it wrong because subtraction can be tricky. But 3 minus 0 is 3, and James wrote 3, so his answer is exactly right.

    The idea underneath. When you check someone's subtraction, work it out yourself first. Then compare to see if their answer is the same, just 1 off, or far off.

  2. 2On level
    Find the missing number.
    5−2=00‾\displaystyle 5 - 2 = \underline{\phantom{00}}
    A
    5
    B
    2
    C
    4
    D
    3
    Show the answer and how to solve it

    The missing number is 3. Start at 5 and count back 2: first to 4, then to 3.

    1. 1Look at the equation. We need to find what is missing.
    2. 2To take 2 away from 5, start at 5 and count back 2 numbers.
    3. 3After counting back 2, we land on 3. So 5−2=35 - 2 = 3.

    Common mistake. A common mistake is picking 5 (the starting number) or 2 (the number being taken away) instead of finding what is left. Remember to start at 5 and count back 2 to get 3.

    The idea underneath. To subtract, start at the bigger number and count back. 5−25 - 2 means count back 2 from 5: first 4, then 3.

  3. 3On level
    What number goes in the blank?
    0+4=00‾\displaystyle 0 + 4 = \underline{\phantom{00}}
    A
    5
    B
    3
    C
    0
    D
    4
    Show the answer and how to solve it

    The answer is 4. When you have 4 and add 0 more, you still have 4.

    1. 1Look at the equation. We need to find what 0+40 + 4 equals.
    2. 2Start at 0 and count on 4 more: 1, 2, 3, 4.
    3. 3So the answer is 4.

    Common mistake. A common mistake is to pick one of the numbers being added (like 0 or 4) instead of the total. The plus sign means to put BOTH numbers together to find how many in all.

    The idea underneath. Adding two numbers means putting them together to find how many in all. You can start with one number and count on the other.

  4. 4Stretch
    Solve.
    3+0=?\displaystyle 3 + 0 = ?
    A
    4
    B
    2
    C
    3
    D
    0
    Show the answer and how to solve it

    The answer is 3 because 3+0=33 + 0 = 3. Adding 0 means nothing is added, so you stay at 3.

    1. 1Look at the equation. We need to add 3 and 0.
    2. 2Start at 3 and count up 0 more: you stay at 3.
    3. 3The answer is 3.

    Common mistake. A common mistake is thinking the answer must change when you add. Adding 0 means nothing is added, so the answer is still 3.

    The idea underneath. When you see +, count up. When you see −, count back. The symbol tells you what to do.