Free printable practice
Adding Missing Addend Sum Under 20 Practice Activities
Printable Class 2 maths worksheets for finding missing addends in addition facts with sums under 20.
Practice that builds confidence
What this skill builds
These Class 2 maths worksheets help children find the missing number in addition sentences where the total is less than 20, such as 8 + __ = 13 or __ + 6 = 15. Children practise thinking about addition as a relationship between parts and a whole, not just as counting forward.
The printable activities include missing addend equations, number bond-style practice, picture-supported questions, and mixed layouts that encourage children to use counting on, related subtraction, and mental maths within 20.
Missing addend practice helps children understand that an addition sentence has two parts that make one total. In questions like 7 + __ = 12, the child is not simply “adding 7”; they are finding the part that completes 12. This strengthens number sense, number bonds under 20, and early algebraic thinking in a Class 2-friendly way.
How the worksheets progress
The activities begin with clear sums under 10 and then move towards totals up to 19. Children may see the blank at the end, in the middle, or at the start of the equation, so they learn that __ + 5 = 11 means the same relationship as 5 + __ = 11. Some pages use visual groups or simple number bond layouts before moving to number-only questions.
A simple parent routine
At home, ask your child to read the full equation aloud: “Eight plus something equals thirteen.” Then let them choose a method. They can count on from 8 to 13, use fingers, draw quick dots, or think “13 minus 8.” After each answer, ask, “Does it make the sentence true?” This checking habit is especially useful when the blank appears before the plus sign.
Classroom uses for teachers
Teachers can use these printables for maths practice after teaching addition facts, for revision of number bonds, or as independent work during centres. They also work well for quick small-group support: one group can use counters or ten frames, while another solves mentally and explains the strategy used.
Common errors to watch for
Some children add all the visible numbers, writing 20 for 8 + __ = 12 because they combine 8 and 12. Others always count from 1 instead of counting on, which can lead to mistakes. Encourage children to identify the total first, circle it if needed, and then find the missing part.
Free printable PDF download
Use this Class 2 missing addend worksheets under 20 page to preview the activity, print it, or download it as a PDF for quick practice. It works well for homework, homeschool lessons, tutoring, morning work, revision, and classroom centers.
Answers and answer key support
After the child completes the worksheet independently, parents and teachers can use the answer support or answer key information to check the work, review mistakes, and choose the next practice step.
Why iBloom worksheets help
iBloom worksheets give repeated, varied practice without overwhelming children. The sums stay under 20, so learners can focus on the missing addend idea, use familiar addition facts, and gradually move from concrete counting to confident mental maths. A child-friendly strategy is: start at the known addend, count up to the total, and the number of steps is the missing addend.
Helpful answers
Frequently asked questions
What is a missing addend in Class 2 addition?
A missing addend is the unknown part in an addition sentence. For example, in 9 + __ = 14, the child must find the number that joins with 9 to make 14.
Which strategy should my child use for sums under 20?
Counting on is a good first strategy: start at the known addend and count up to the total. Children can also use related subtraction, such as solving 15 - 6 to answer 6 + __ = 15.
Why are the totals limited to under 20?
Totals under 20 keep the number range familiar for Class 2 learners. This lets children focus on understanding the missing part rather than struggling with large calculations.
How can I help if my child adds the two visible numbers?
Ask your child to find the total first and say the equation in words. For 7 + __ = 12, they should understand that 12 is the whole and 7 is one part, so they need the other part.
Can these worksheets be used after learning number bonds?
Yes. Missing addend questions are a useful next step after number bonds because children apply the idea that two parts combine to make a total.
Is this Class 2 missing addend worksheets under 20 free?
Yes. You can preview it for free and use the printable worksheet for home or classroom practice.
Can I download this Class 2 missing addend worksheets under 20 as a PDF?
Yes. Use the worksheet download option to save a printable PDF, or print the worksheet directly from the page.
Does this Class 2 missing addend worksheets under 20 include answers or an answer key?
When the activity has fixed answers, iBloom includes answer support so parents and teachers can check the completed worksheet.