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Halving and Doubling Number Towers

Worksheet Description

Build vertical number towers by halving or doubling 10 times. See numbers shrink or grow step by step using left-to-right mental maths

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Introduction

This worksheet introduces a visual and engaging way to practice repeated halving and doubling through vertically stacked number towers. Learners build each tower step by step, observing how numbers shrink or grow through successive mental calculations.

Understanding Number Towers

A Number Tower is formed by placing each new result directly below the previous one, creating a vertical sequence of calculations.

Each row in the tower represents another halving or doubling operation, allowing learners to see numerical change unfold step by step.

Halving Towers

In a Halving Tower, a large number appears at the top of the tower. The learner successively halves the number up to ten times, entering each result in the input boxes below.

Example:

  1. 16793683968
  2. 8396841984
  3. 4198420992
  4. 2099210496
  5. 104965248
  6. 52482624
  7. 26241312
  8. 1312656
  9. 656328
  10. 328164

Doubling Towers

In a Doubling Tower, a smaller starting number is displayed at the top. The learner doubles the number successively ten times, with each new result forming the next row in the vertical tower.

This repeated doubling helps learners develop a strong intuitive sense of exponential growth and powers of two.

Left-to-Right Mental Strategy

As with the Practice Halving and Doubling the Numbers worksheet, all calculations should be done mentally from left to right using place-value breakdown.

Enter answers from left to right

Learners should avoid digit-by-digit computation and instead view each number as a whole made of hundreds, tens, and ones, operating on these chunks sequentially.

Exploring Patterns and Extra Challenges

This worksheet also encourages deeper exploration of numerical patterns.

  • Divide the second row by 4 instead of halving the first row
  • Divide the third row by 8 to verify powers-of-two relationships

These variations help learners recognize consistent scaling patterns and strengthen their understanding of exponential change.

Visualizing Growth and Reduction

Working vertically allows learners to see how numbers expand or contract with each operation.

Each new row represents another multiplication or division by 2, reinforcing the visual and conceptual meaning of halving and doubling.

Skills Developed Through Number Towers

  • Strong understanding of halving and doubling patterns
  • Improved left-to-right mental calculation speed
  • Clear visualization of exponential growth and reduction
  • Enhanced number sense and mental agility

Online, Interactive, and Self-Correcting

This is an online, interactive worksheet where learners enter each halved or doubled value directly into vertically arranged input boxes.

Answers are checked instantly, allowing immediate feedback and correction. No printing or downloading is required.

Click on the green box in the first problem of the worksheet to get started!!