Number (add/sub)
UK Primary (3-6)
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Addition fact families (a+b=c, c-b=a)
Lesson

A fact family describes a relationship between 3 numbers.  The relationship could be through addition or subtraction.  

This video shows how we can use fact families to help us answer questions. 

Worked Examples

Question 1

We are interested in the fact family of $1$1,$8$8 and $9$9.

$+$+ $=$=
$8$8 $+$+ $1$1 $=$= $9$9
  1. What is $1+8$1+8?

  2. What is $9-8$98?

  3. What is $9-1$91?

Question 2

We are interested in the fact family of $2$2, $4$4 and $6$6:

$-$ $=$=
$6$6 $-$ $4$4 $=$= $2$2
  1. What is $2+4$2+4?

  2. What is $6-2$62?

  3. What is $4+2$4+2?

Question 3

We are interested in the fact family of $2$2,$4$4 and $6$6:

$+$+ $=$= ?
$2$2 $+$+ $4$4 $=$= ?
  1. What is $2+4$2+4?

  2. What is $4+2$4+2?

  3. What is $6-4$64?

  4. When looking at the answer to $6-2$62, is the answer going to be less than $10$10?

    Yes

    A

    No

    B

    Yes

    A

    No

    B
  5. What is $6-2$62?

 

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