What happens when you add 10 to a number?

17 + 10 = ?

In this lesson you will learn to add 10 to a number by using ten-frames and a 100 chart.

Let’s Review

The ones number stays

the same.

Adding 10 to a number in the ones row

6 + 10 = 1610 + 6 = 16

Let’s ReviewSubtracting 10 from a

number in the ‘teens’ row

16- 10 = 6The ones

number stays the same.

Let’s ReviewPlace Value- tens and ones

5 ones2 tens 25

20 5 20 + 5 = 25

Let’s ReviewCounting by 10s

10, 20, 30, 40, 50, 60, 70, 80, 90, 100

Start at any number and

count by tens.

5, 15, 25, 35, 45, 55, 65, 75, 85, 95

Let’s ReviewCounting by 10s

100, 90, 80, 70, 60, 50, 40, 30, 20, 10

We can count backwards by

10.

95, 85, 75, 65, 55, 45, 35, 25, 15, 5

A Common MisunderstandingThose confusing ‘teen’ numbers.

14 41fourteen forty-one1 ten4 ones

4 tens1 one

They sound alike, but they are not the same.

Core LessonAdding 10 to a number

Plus 1017 + 10 = 27

10, 20, 21, 22, 23, 24,

25, 26, 27

Started with 17 and counted on 10.

Core LessonPlus 10

48 + 10 = 58

10, 20, 30, 40,50

8 more is 58

48

Core LessonPlus 10

48 + 10 = 58

It’s like skip counting by 10

48, 58

48

Core LessonPlus 10

35 + 10 = 45

30 + 10 = 4040 + 5 = 45

35

3 tens and 1 ten is 4 tens.

It’s 45.

Core LessonPlus 10

21,31The tens goes

up by 1.

21 + 10 = 31

21

Core LessonAdding 10 to a number

Start Number

End Number

               

17

31455827

48352152 ?62

Core Lesson10 More

13 + 10 24 + 1062 + 1076 + 1047 + 1059 + 10

Try these in your head.

Core Lesson10 More

13 + 10 = 23 24 + 10 = 3462 + 10 = 7276 + 10 = 8647 + 10 = 5759 + 10 = 69

Only the tens change.

Core Lesson What do you notice?When we add 10

• The ones stay the same.• The tens number goes

up by 1 ten.• On the 100 chart, the

end number is below the start number.

In this lesson you learned to add 10 to a number by using ten-frames and a 100 chart.