지도서 · Part 2 · 3 / 8

Fact families수 가족

Three numbers, four facts.

Step 2워크북 7–8쪽 →
한국어 요약

세 수로 덧셈 두 개와 뺄셈 두 개를 만드는 수 가족(fact family)을 영어로 가르치는 법이에요. whole과 part라는 말, 뺄셈은 늘 전체에서 시작한다는 점을 작은 물건과 부분-전체 그림으로 보여 줘요.

이 주제의 단어fact family
이 주제 차례 (8)

The big idea핵심

Three numbers like 9, 4 and 13 make a fact family. They give four facts: 9 + 4 = 13, 4 + 9 = 13, 13 − 4 = 9, 13 − 9 = 4. Adding and subtracting are opposites: one puts together, one takes apart. We can add in any order, but when we subtract we must start with the whole (the biggest number).

1394
whole 13, parts 9 and 4
1394
the same family as a bar model

Get ready준비물

  • 13 counters in two colours (9 of one colour, 4 of another)
  • Paper with a part–whole model drawn on it (three circles)
  • A pencil

Teach it, step by step단계별 수업

YOU 부모가 할 말LIA 아이가 할 만한 대답DO 손으로 할 일

Make the whole and the parts

DOPut 9 red and 4 blue counters in the whole circle.
YOU“How many altogether?”
LIA13.
YOU“This is the whole. The whole is 13.”
DOMove the red ones to one part circle and the blue ones to the other.
YOU“Now we have two parts. The parts are 9 and 4.”

Two adding facts

YOU“9 and 4 make 13. So 9 + 4 = 13.”
YOU“Can we start with 4? 4 and 9 make…?”
LIA13 too!
YOU“Yes! We can add in any order. The answer is the same.”

Two taking-away facts

DOPut all 13 back in the whole. Now take away the 4 blue ones.
YOU“What is left?”
LIA9.
YOU“So 13 − 4 = 9. Now start again and take away the 9 red ones. What is left?”
LIA4.
YOU“So 13 − 9 = 4.”

Why we start with the whole

YOU“Can we do 4 − 13?”
LIANo…
YOU“In Year 2 we always start with the whole, the biggest number. The whole goes first when we take away.”

Write the family

YOU“Let's write all four facts. Two with plus and two with minus.”
YOU“Which number is in every fact?”
YOU“Which number is always first in the minus facts?”
LIA13, the whole.
광고

Other ways to say it다른 표현

  • “What is the whole?”
  • “What are the parts?”
  • “The whole is 13. One part is 9. What is the other part?”
  • “Write the fact family for 9, 4 and 13.”
  • “If you know 9 + 4 = 13, what else do you know?”
  • “Can you write a related fact?”
  • “Can you write it the other way round?”

Good questions to ask좋은 질문

  • “If you know 9 + 4 = 13, what else do you know?”

    Note

    The best question for this topic. Aim for all three other facts.

  • “Is 13 − 4 = 9 true or false? How do you know?”

  • “Which number is the whole? How can you tell?”

    Note

    It is the biggest one.

  • “Why does 4 + 9 give the same answer as 9 + 4?”

    Good answers

    “They are the same parts, just in a different order.”

  • “Is 4 − 13 = 9 true?”

    Note

    False. Explain: we start with the whole.

If Lia is stuck막힐 때

  • When

    She writes 4 − 13 = 9.

    Point to the part–whole model. “Where do we start when we take away? At the top, the whole.”

  • When

    She writes only 2 or 3 facts.

    “A family has four people: two plus facts and two minus facts. Who is missing?”

  • When

    She does not know which number is the whole.

    “The whole is made of the parts, so it is the biggest.” Show it with counters.

Games (2)놀이

Game · Fact family houses

You need: paper and pens

  1. Draw a house. Write the whole (for example 12) in the roof.
  2. Draw two doors with the parts (7 and 5).
  3. Draw four windows. Lia writes one fact in each window.
  4. Then Lia makes a house for you. Make one mistake on purpose. Can she find it?
Game · Mystery part

You need: counters and a cup

  1. Show 11 counters: “The whole is 11.”
  2. Hide some under the cup. Show 5: “One part is 5. What is the mystery part?”
  3. Lia answers with a full sentence: “The mystery part is 6, because 5 and 6 make 11.”

Extra challenge더 도전

  • Families with bigger numbers: 30, 40 and 70. (“30 + 40 = 70, 40 + 30 = 70, 70 − 40 = 30, 70 − 30 = 40.”)
  • Can a fact family have only two facts? Yes, when the parts are the same: 5 + 5 = 10 and 10 − 5 = 5.
  • Find a fact family where the whole is 20.
In the workbook

Part–whole models, bar models, true or false, and a story about marbles.

워크북 7–8쪽 보기이 주제 인쇄

자주 묻는 질문

왜 family라고 하나요?

같은 세 수로 이어진 식들이라서 한 가족처럼 불러요.

5, 5, 10처럼 같은 수가 둘이면요?

5 + 5 = 10, 10 − 5 = 5 두 식만 나와요.

광고