Mathematics Grade 12 15 min

Count on twenty frames (up to 20)

Count on twenty frames (up to 20)

What you'll learn

  • Count up to 20 objects using a twenty frame with one-to-one correspondence.
  • Identify the number represented on a filled twenty frame (up to 20).
  • Fill a twenty frame with the correct number of counters when given a number between 1 and 20.
  • Given two twenty frames (each with less than 10 dots), add the number of dots from each frame to find the total (up to 20).

Tutorial Preview

1

Introduction & Learning Objectives

Learning Objectives Define the concept of a limit using the finite model of a twenty frame. Express the process of filling a twenty frame using formal one-sided limit notation. Model the state of a twenty frame as a discrete sequence and determine its limit as the number of terms approaches its maximum. Apply the epsilon-N definition of a sequence limit to prove the limit of a twenty-frame system. Identify and explain the concept of jump discontinuity by analyzing the process of adding dots to a twenty frame over time. Translate the abstract concept of a limit from the twenty-frame model to foundational calculus problems. Imagine filling a container with exactly 20 items. As you add the 18th, 19th, and final 20th item, you are intuitively 'approaching' a maximum. H...
2

Key Concepts & Vocabulary

TermDefinitionExample The Limit of a SequenceThe value that the terms of a sequence 'approach' as the term number 'n' gets very large or approaches a specific value. In our model, the sequence is the number of dots, and the limit is the frame's capacity.Let the sequence `a_n` be the number of dots in the frame after `n` dots have been added. The sequence is `1, 2, 3, ..., 20`. The limit as `n` approaches 20 is 20. Twenty Frame Sequence (a_n)A finite, ordered list of numbers representing the state of the twenty frame at each step. We define it as `a_n = n` for `1 ≤ n ≤ 20`.`a_1 = 1` (one dot), `a_5 = 5` (five dots), `a_{20} = 20` (twenty dots). Limit from the Left (One-Sided Limit)Approaching a limit from values that are less than the target value. This is the only...
3

Core Formulas

Limit of the Twenty Frame Sequence \lim_{n \to 20} a_n = L This formula states that the limit of our sequence `a_n` (where `a_n = n`) as the step number `n` approaches its maximum value of 20 is equal to the Limit `L`, which is 20. One-Sided Limit Notation \lim_{n \to c^-} a_n = L This specifically describes approaching the target value `c` (for us, 20) from values of `n` that are less than `c`. The superscript minus sign indicates an approach 'from the left' or 'from below'. Epsilon-N Definition of a Sequence Limit \forall \epsilon > 0, \exists N \in \mathbb{Z}^+ \text{ such that } \forall n > N, |a_n - L| < \epsilon This is the formal definition of a limit. It means: For any tiny positive distance `ε` you choose, we can find a step `N`...

4 more steps in this tutorial

Sign up free to access the complete tutorial with worked examples and practice.

Sign Up Free to Continue

Sample Practice Questions

Easy
In the context of the twenty-frame model, what does the value 'L' represent in the formal limit expression lim_{n → 20} a_n = L?
A.The current number of dots in the frame
B.The maximum capacity of the frame
C.The next dot to be added
D.An arbitrarily small positive number
Easy
The state of the twenty frame is modeled by the discrete sequence a_n. According to the tutorial, what is the correct definition of this sequence?
A.a_n = 20 for 1 ≤ n ≤ 20
B.a_n = n for 1 ≤ n ≤ 20
C.a_n = n + 1 for 1 ≤ n ≤ 19
D.a_n = 20 - n for 1 ≤ n ≤ 20
Easy
Which term describes a point in a function where the value abruptly changes from one value to another without taking on any intermediate values, as seen when adding a single dot to the twenty frame?
A.Limit
B.Continuous function
C.Jump discontinuity
D.Epsilon tolerance

Want to practice and check your answers?

Sign up to access all questions with instant feedback, explanations, and progress tracking.

Start Practicing Free

More from Introduction to limits

Mathematics for other grades

Frequently asked questions

What grade level is "Count on twenty frames (up to 20)"?

Count on twenty frames (up to 20) is a Grade 12 Mathematics lesson on ExcelOS.

What will I learn in Count on twenty frames (up to 20)?

You'll be able to: Count up to 20 objects using a twenty frame with one-to-one correspondence; Identify the number represented on a filled twenty frame (up to 20); Fill a twenty frame with the correct number of counters when given a number between….

Is "Count on twenty frames (up to 20)" free to practice?

Yes. You can read the tutorial preview for free, and signing up for a free ExcelOS account unlocks the full tutorial and all practice questions with instant feedback.

How many practice questions are included with Count on twenty frames (up to 20)?

This lesson includes 25 practice questions across multiple difficulty levels, each with instant feedback and explanations.

Ready to find your learning gaps?

Take a free diagnostic test and get a personalized learning plan in minutes.