➕➖ Adding and Taking Away up to 20
Class 1 Maths · Unit 6 of 12 · about 120 minutes
Builds on addition and subtraction within 10 to extend to totals up to 20. Children use counting on and counting back on a number line, make ten to add, and solve simple word problems. This unit prepares for place value and mental arithmetic in later grades.
What your child will learn
- Students will be able to add two numbers with a sum up to 20 by counting on from the larger number.
- Students will be able to subtract a number from a number up to 20 by counting back on a number line.
- Students will be able to use the make-ten strategy to add numbers with a sum up to 20.
- Students will be able to solve simple word problems involving addition and subtraction up to 20.
Lessons in this unit
- Count on to add: Add two numbers with sum up to 20 by counting on from the larger number. Use a number line and objects.
- Count back to subtract: Subtract a number from a number up to 20 by counting back on a number line or with objects.
- Make ten to add: Use the make-ten strategy to add numbers with sum up to 20, especially when one addend is 8 or 9.
- Word problems: Solve simple addition and subtraction word problems up to 20 using objects, drawings, or number lines.
Key words
- add
- Put together to find how many in all.
- take away
- Remove some to find how many are left.
- count on
- Start from a number and count forward.
- count back
- Start from a number and count backward.
- number line
- A line with numbers in order that helps us count.
- make ten
- Put numbers together to make 10 first.
- sum
- The answer when we add.
- difference
- The answer when we take away.
Help your child at home
What to watch for
- Counting on from the smaller number is just as easy.
- Help: Show that starting from the larger number means fewer jumps.
- Subtracting zero means the answer is zero.
- Help: Show that subtracting zero means nothing is removed, so the number stays the same.
- The number broken off is forgotten after making ten.
- Help: Always write the leftover part and add it to 10.
- Every word problem with 'more' means addition.
- Help: Read the story carefully and act it out with objects.
Try this at home
- Number line jumps: 8 + 5 — start at 8, five +1 jumps to 13
- Number line jumps: 15 − 6 — start at 15, six −1 jumps back to 9
- Ten-frame: 9 + 6 — move 1 from the 6 to fill the frame (10), 5 are left → 10 + 5 = 15
- Addition: 'Kabir has 9 marbles, finds 4 more.' Start at 9, count on 4 → 9 + 4 = 13
Quick questions to ask aloud
- What is 8 + 5? (13 / 12 / 14)
Show answer
Start at 8, count 5 more: 9,10,11,12,13. So 8 + 5 = 13. - What is 15 - 6? (9 / 8 / 10)
Show answer
Start at 15, count back 6: 14,13,12,11,10,9. So 15 - 6 = 9. - To add 9 + 6, we make ten. What is 9 + 1? (10 / 9 / 8)
Show answer
9 and 1 make 10. That helps us add faster.
Free printable charts
- Addition Within 20: 24 sums with a make-ten trick and an answer key. (Class 1–2 · ages 6–8, free PDF)
- Subtraction Within 20: 24 take-away sums with a back-to-10 trick and an answer key. (Class 1–2 · ages 6–8, free PDF)
Frequently asked questions
What will my child learn in "Adding and Taking Away up to 20" (Class 1 Maths)?
Your child will be able to: add two numbers with a sum up to 20 by counting on from the larger number.; subtract a number from a number up to 20 by counting back on a number line.; use the make-ten strategy to add numbers with a sum up to 20.; solve simple word problems involving addition and subtraction up to 20..
How does MangoMindz teach "Adding and Taking Away up to 20"?
In 4 short parts (Count on to add, Count back to subtract, Make ten to add, Word problems). Each part has a picture-based lesson read aloud by Mango Teacher, a quick check, and a quiz built from common mistakes children make, with Mango, a study buddy, for questions.
How long does "Adding and Taking Away up to 20" take?
About 120 minutes in total, spread over 4 parts of 15–25 minutes each.
How can I help my child with "Adding and Taking Away up to 20" at home?
Work through a small example together, such as: Number line jumps: 8 + 5 — start at 8, five +1 jumps to 13; Number line jumps: 15 − 6 — start at 15, six −1 jumps back to 9. Then ask a quick question aloud: What is 8 + 5? (13 / 12 / 14)
What mistakes do children often make in "Adding and Taking Away up to 20"?
Counting on from the smaller number is just as easy. Fix: Show that starting from the larger number means fewer jumps. Subtracting zero means the answer is zero. Fix: Show that subtracting zero means nothing is removed, so the number stays the same. The number broken off is forgotten after making ten. Fix: Always write the leftover part and add it to 10.
Is "Adding and Taking Away up to 20" free on MangoMindz?
Yes. Every lesson part and quiz in "Adding and Taking Away up to 20" is free on MangoMindz, with no ads.