Hello, young mathematician! This guide helps you learn addition and subtraction within friendly two-digit situations in a calm, step-by-step way. We will use small stories, clear checks, and original practice so the idea feels useful instead of heavy.
Caregiver: Keep the work hands-on and short. Let the child explain with objects, drawings, or fingers before asking for neat notebook answers.
This original PrincipalSaab guide follows Chapter 6, Decoration for Festival (Addition and Subtraction), from NCERT’s Joyful Mathematics for Class 2. The explanations, examples, activity, and practice here are newly written and do not copy textbook stories, exercises, or artwork.
For a quick warm-up, revisit A Day at the Beach, explore the Class 2 Mathematics learning path, or use Ask a Doubt if you want help with a number story.
Words to Know
add
put together or count on
18 flowers and 7 more flowers
subtract
take away or find what is left
25 lamps, 6 are used
altogether
total after joining groups
12 + 9
left
remaining after some go away
30 – 8
number line
a line used for counting jumps
jump from 18 to 25
Make two paper garlands with small dots. Count the dots on each, join the counts, then cover some dots and say how many are left. Use only paper and crayons. (8-10 min)
Your Learning Plan
- Read the situation slowly.
- Underline the numbers and units in your mind.
- Choose the operation or comparison.
- Work step by step.
- Check whether the answer is sensible.
Count On Addition
Addition can begin from the bigger number. Keep that number in your head, then count the smaller number forward.
Festival decoration problems are friendly because children can imagine flowers, flags, lamps, and beads without copying any textbook picture.
After adding, check whether the answer is bigger than both starting groups. If it is smaller, something has gone wrong.
- Start with 16 yellow paper flowers.
- Add 8 red paper flowers.
- Count on 8 steps using fingers or dots: 17, 18, 19, 20, 21, 22, 23, 24.
Answer: There are 24 flowers altogether.
Take Away Subtraction
Subtraction tells what is left when some objects are used, moved, or covered.
For young learners, crossing out drawn objects or moving counters is a strong first step before writing a number sentence.
When a full ten must be broken, picture opening a ten-bead garland into ten single beads so some beads can be taken away.
After subtracting, check whether the answer is smaller than the starting number.
- There are 32 clay lamps.
- The class places 9 near the door.
- Take away 9: 32 – 9 = 23.
Answer: 23 lamps are left.
Missing Parts
Sometimes the total is known but one part is missing. This is still a subtraction idea.
Use a simple box: part plus missing part equals whole. The missing part is found by taking the known part away from the whole.
Children may also count up from the known part to the whole. Both methods are useful.
- The wall needs 40 flags.
- Children have made 27 flags.
- Count up or subtract: 40 – 27 = 13.
Answer: 13 more flags are needed.
Friendly Tens
Making ten helps addition become calmer. 18 + 7 can become 20 + 5.
In Class 2, this should feel like moving counters, not like a rule to memorise.
For subtraction, the opposite action can help: open one ten like a garland, then take away the needed ones.
Whenever a number is close to 10, 20, 30, or 40, ask whether making the next ten helps.
- For 18 + 7, give 2 from 7 to 18.
- 18 becomes 20.
- 5 remains, so 20 + 5 = 25.
Answer: 18 + 7 = 25.
Story Problems
A story problem should be read slowly. First decide whether groups are joining or something is going away.
Underline the action words in your mind: more, altogether, left, used, given, broken, or needed.
Then write a short number sentence and answer in words.
- One row has 14 dots and another has 15 dots.
- Join the two rows: 14 + 15 = 29.
- 29 is bigger than 14 and 15, so the answer is sensible.
Answer: The plan has 29 dots.
Check With Objects
A Class 2 child should not feel that the written sum is the only way to do mathematics. Objects and drawings are honest tools. They show what the numbers mean before the child writes the final sentence.
For addition, place the first group in one row and the second group in another row. Push the rows together only after both groups have been counted. Then count the total and say the unit: flowers, beads, flags, dots, or stickers.
For subtraction, start with the full group. Move away or cover the number that is used, given, or lost. Count only what remains. This helps children see that subtraction is not just saying a smaller number; it is a clear action.
For a missing part, show the whole first. Then cover the known part and count the uncovered part. This makes questions like “How many more are needed?” feel less mysterious.
After the object check, write one short number sentence. The object work and the written work should tell the same story.
Practice Time
Try each original prompt first. Open the answer only after you have made your own attempt.
Practice 1. 18 paper flowers and 7 more are joined. How many flowers are there?
Answer: 25 flowers.
Practice 2. 30 stars are cut. 8 are used on a card. How many are left?
Answer: 22 stars.
Practice 3. A class needs 40 flags and has 26. How many more are needed?
Answer: 14 flags.
Practice 4. Complete: 19 + 6 = __.
Answer: 25.
Practice 5. Complete: 34 – 9 = __.
Answer: 25.
Practice 6. There are 12 green beads and 13 blue beads. Find the total.
Answer: 25 beads.
Practice 7. A strip has 28 stickers. 11 fall off. How many stay?
Answer: 17 stickers.
Practice 8. Which is sensible for 21 + 8: 13, 29, or 82?
Answer: 29.
Caregiver Tips for Review
- Ask the child to explain one answer aloud: what the numbers mean, which operation was chosen, and how the result was checked.
- When the child is unsure, return to objects or drawings such as counters, dots, a marked line, or a short table.
- Write only one or two neat notebook problems at a time so each answer can be checked calmly.
- Ask, “What would be too small? What would be too large?” to build a quick reasonableness check.
- If two methods give the same answer, name both methods, such as counting on and checking with subtraction.
- Vary the objects while keeping the same idea clear: change flowers to beads, shells to pebbles, or flags to leaves.
- Let a quick child still explain the path, and let a slower child use drawings without hurry.
Kaizen step: Do one small correct check today. Tomorrow, do one more. Calm practice builds strong maths.
Continue Learning
- Browse PrincipalSaab Study Notes
- Open the CBSE learning hub
- Next in Joyful Mathematics: continue with the next official chapter after this one.