It is very common for students to have difficulty with the numbers 11 19. Their
names do not follow a pattern and must be considered sight words/ numbers of
mathematics. Teachers must ACTIVELY help students develop meaning for both the
words and the corresponding numerals.
There are many intervention strategies to help students make sense of the "teen numbers from 1119."
www.mathwire.com has the following suggestions:
1. First, work on rote counting from 1020.
 Identify the student's comfort zone: add 12
numbers at a time to the 110 sequence until the student can reliably count on
using the correct names.
 Sing songs and extend counting songs: for example,
Ten Little Indians can be modified and extended to be 11 little,
12 little, 13 little teddy bears (or dinosaurs or valentines, etc.). Singing is
great reinforcement for many students and helps them acquire fluency with these
extended numbers more easily than simply counting aloud.
 Who Has The Number?: Give students the large demosize cards (#1020) and have them hold up the cards as you
sing the song so that students hear and see the numbers.
 Teen Lineup: distribute the large demosize cards (#1020) and ask students to line up in the correct
order. NOTE: numbers 10 and 20 of the teen demo cards are boxed in bright orange
[see picture at left] to visually reinforce the notion that the teen numbers are
between 10 and 20. Reinforce this notion often when
working with the teen demo cards.
2. Learn to recognize the teen numbers.
 Matching Station: Provide many copies of the teen
number cards for students to match to teen numbers in sequential order.
 Matching Singalong: As students sing extended
teen number songs, have students point to teen number cards to imprint written
number with the oral name.
 Teen LineUp: students shuffle number cards, then
place them in sequential order. After this, students point to each number and
name it.
 Teen Swiper: One student places the teen numbers
in sequential order on the floor then removes a card while the other student has
eyes closed. This student opens eyes and names the missing number. He/she must
then locate that number in a second pile of all teen numbers and place it in the
correct place. For this game, it is helpful to have two decks printed on
different color paper, or in different color fonts for easy separation into two
complete decks.
3. Next, attach meaning to the number.
 Fourhanded Teens: Have student pairs represent
teen numbers. One student holds up both hands to represent 10 fingers. The other
student shows additional fingers to represent the teen number.
 Stamping sets: Give student number cards and have
student stamp that many objects on the card.
 Teen Number Posters: Hang number posters for numbers 1120 on classroom walls. These posters
include the baseten representation of each number. Regularly include these in
rote counting activities, counting 120 while pointing to the posters. Introduce
the teen numbers as between 10 and 20.
 Teen Number Mats: Provide number card mats for each
number 1119 and have students count aloud as they place counters on the mat.
(Modification would be providing dots on which students place the counters as
they count aloud.) NOTE: There is no effort to group materials or make tens at
this stage. Students are simply attaching rote counting to onetoone
correspondence and the beginning of number recognition.
4. Learn to model numbers to make sense of the number value and number sequence.
 Use of BaseTen Blocks: This should follow lots of
practice with nongrouped materials and students should use baseten blocks and
a placevalue mat concretely,
writing only the answer to modeling the numbers to attach meaning to how many
ones and how many tens they have.
 Pictorial Representation: Be sure to model for
students how they can use simple lines and dots to represent the baseten blocks
to record their thinking. This semiconcrete step is often skipped when teachers
go from concrete (baseten blocks) to abstract (numbers on a page). Students who
use this pictorial step have access to more powerful mathematical reasoning by
using this intermediate step to think through problems beyond
what they have learned.
 Overhead practice: after students have had lots
of handson experience, use an overhead to present either the blocks alone or
the number alone and ask students to quickly model the number on their placevalue mats, filling in the missing information.
I'm going to add my own activity at this point... learning to recognize that teen numbers are composed of "ten and a specific number of "more"... which helps to attach meaning to the number. In addition, the teen 10 frames cards also help students to see and interact with the model to make sense of the number value.
Ten frames are an invaluable resources to visualize this concept of ten plus a specific number of more.
So I created a set of eyecatching snowmen demonstration ten + frame cards from 1020 in both demonstration size and 4 on a page size , a set of expressions strips from 10 + 0 = through 10 + 10 =, and a set of equation cards in which the word for the teen is featured in both English and Spanish, i.e. 10 + 4 = fourteen, 10 + 4 = catorce.

4 of the suggestion cards based on Debbie Diller's "I Can" cards 

10 frame card set with 8 suggested games
Deborah 
This ten frame set can be purchased at either my Teachers Pay Teachers store , or you can make your own cards using my pictured examples to help you.