Addition within 10

1Summary 重點摘要

Addition means putting two groups together and counting the total.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Step 1: Adding is putting togetherAdding means putting two parts together to find the total; this is the most basic meaning of addition. Why do we learn it? Because life often asks us to join two piles into one. Example: put 3 apples on a plate, then add 2 more; counting them together makes 5, so we write 3 + 2 = 5. Take care that after joining, you count all of them again; do not count only the part just added, or the total will come out wrong.
2. Step 2: Read the symbolsEach symbol in a sum has its own meaning, and reading them correctly comes before any working. The + sign means put the two sides together, and = means both sides have the same amount. Example: 3 + 2 = 5 reads 'three plus two equals five'; say the symbols out loud too, and the sum is read in full. The usual error is treating + as a minus, or skipping the = and writing an answer straight away; one misread symbol ruins the whole sentence.
3. Step 3: Use fingersFingers are counting tools you always carry, ready to help at any moment. Each finger stands for one thing, so the number of fingers shown matches the number counted. Example: for 4 + 3, hold up 4 fingers, then 3 more, and count them all: 1, 2, 3, 4, 5, 6, 7. Seven fingers in all, so 4 + 3 = 7. Count slowly one finger at a time; never skip a finger and never count the same finger twice.
4. Step 4: Count onTo add, keep the bigger number in your head and count on from there; this method is called counting on. Why start from the bigger number? Because far fewer steps are then needed. Example: for 6 + 3, remember 6 and count on 7, 8, 9; three steps taken, so the answer is 9. The most common mistake is counting the big number itself as the first step, which adds one step too many; the first number you say must always be the one after the big number.
5. Step 5: Order does not matterWhen two numbers are added, swapping their places does not change the answer; this is an important rule of addition. Why is it the same? The same things are put together, and which pile goes first does not change the total. Example: 2 + 5 = 7 and 5 + 2 = 7 too. With this rule, whichever number comes first, you can add with confidence. Remember the rule holds for addition only; in subtraction, swapping the two numbers changes the answer, so never mix the two cases.
6. Step 6: Adding zeroZero means nothing at all, so adding 0 adds nothing and the total stays the same. Example: 4 + 0 = 4; you had 4 sweets and got 0 more, so there are still 4 sweets, not one more. Any number plus 0 stays that same number. The common error is writing 0 as the answer on seeing + 0, forgetting the original number; adding 0 means keeping the number unchanged, not turning it into 0, and the two are exact opposites.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• Addition means putting groups together.
• + is plus, = is equals.
• Count on: for 6 + 3 count 7, 8, 9.
• Order does not matter: 2 + 5 = 5 + 2.
• Adding 0 changes nothing.