Addition Within 20
This topic covers 5 learning steps, guiding your child from the basics through to confident problem-solving. Each step includes a worked example and adaptive practice questions.
What Your Child Will Learn
- Add within 10
Add two numbers within 10 - Add to make teens
Add to get numbers 11-15 - Add within 20
Add two numbers up to 20 - Add three numbers
Add three small numbers - Missing addends
Find the missing number: ? + 5 = 12
Common Mistakes
- Starting the count from the wrong number (e.g. for 8+3, counting "8, 9, 10" and getting 10 instead of 11)
When counting on, the first number you say should be the NEXT number after the starting number. For 8+3, count "9, 10, 11" — hold up a finger for each count. - Confusing addition with subtraction signs
The plus sign (+) means "put together" or "add more." Practise reading number sentences aloud: "eight PLUS three equals eleven." Consistent language helps children distinguish the operations.
Tips for Parents
- Use building bricks — snap two groups together and count the total. This makes addition physical and visible.
- At mealtimes: "You have 5 peas and I give you 3 more — how many peas now?" Real food makes real maths.
- Draw number lines on paper and hop along them together. Start at one number and jump forward to add.
- Play board games with two dice — adding the numbers together is natural addition practice.
Key Words
- Add — Combine two groups to find how many altogether.
- Plus (+) — The symbol that means "add together."
- Equals (=) — The symbol that means "is the same as."
- Sum — The answer to an addition.
- Count on — Start from one number and count forwards to add more.
Where This Fits
Before this topic: Children should know number bonds to 10 and be able to count reliably to 20.
After this topic: Addition within 20 prepares children for addition within 100 in Year 2, using place value and column methods.
How MathCraft Teaches This
In MathCraft, Addition Within 20 is taught through the Algebra & Arithmetic adventure track. Your child follows guided lessons with friendly characters, works through examples step by step, then practises with questions that adapt to their level.
The adaptive engine tracks mastery across all 5 steps, revisiting concepts your child finds tricky and advancing when they're ready. Parents can see detailed progress in the Parent Dashboard.
Practise Addition Within 20 with MathCraft
Step-by-step lessons, worked examples, and adaptive practice — all wrapped in an adventure game your child will love.
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