UK Primary (3-6) Lesson

Here we will use patterns in addition to help us add two-digit and single-digit numbers. When adding ten to one addend (number), we can see a pattern in the answer.

#### For example:

$6+2=8$6+2=8

$16+2=18$16+2=18

$26+2=28$26+2=28

$36+2=38$36+2=38

Do you notice how the digit in the ones column stays the same and the tens digit increases by one ten each time? Let's use that knowledge to learn more about patterns in addition.

Key vocabulary

Commutative law: numbers can be added in any order, e.g. $5+3$5+3 is the same as $3+5$3+5.

Number sentence: a way of writing a mathematical fact using numbers and operators (e.g. +, -, x or ÷)

#### Worked Examples

##### question 1

$17+2=19$17+2=19

Use this to find:

1. $27+2=\editable{}$27+2=

2. $37+2=\editable{}$37+2=

3. $47+2=\editable{}$47+2=

4. $67+2=\editable{}$67+2=

##### question 2

$5+13=18$5+13=18

Use this to find:

1. $5+\editable{}=28$5+=28

2. $5+\editable{}=38$5+=38

3. $5+\editable{}=48$5+=48

4. $5+\editable{}=88$5+=88

5. What is the pattern? Choose the correct answer:

A two digit number plus $5$5 always has the same answer.

A

When we add $5$5 to a two-digit number that ends in $3$3, we get a two-digit number that ends in $8$8.

B

The tens digit never changes when we add $5$5 to any number.

C

There is no pattern.

D

A two digit number plus $5$5 always has the same answer.

A

When we add $5$5 to a two-digit number that ends in $3$3, we get a two-digit number that ends in $8$8.

B

The tens digit never changes when we add $5$5 to any number.

C

There is no pattern.

D

##### question 3

1. $3+32$3+32 will be in the:

$40$40s

A

$30$30s

B

$40$40s

A

$30$30s

B