Number Lines: Proportionality [TEKS Tools Grade 7]

This post specifically looks at how number lines can be used solve problems involving proportions and similar shapes. Read more about TEKS Tools and their rationale here.

Number Lines

Number lines account for around 30% of each 7th grade STAAR test. These number lines are applied to solve problems related to ratios, rates, percents, scale, and operations.

The main function of a number line is to solve problems involving operations, understand ratios, rates, and proportionality, or as a tool to explore scale and percent increase/decrease. By visualizing these quantities on number lines, students can better make sense of the how the quantities are related.

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Proportions

The constant of proportionality is the ratio of y with respect to x.

7.4C - determine the constant of proportionality (k = y/x) within mathematical and real-world problems

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2024-8: a proportion was given, students had to find the constant of proportionality

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Units can be converted using proportions.

7.4E - convert between measurement systems, including the use of proportions and the use of unit rates

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2024-9: a unit conversion was given, students had to find a related length

2025-37: a unit conversion was given, students had to find a related length and identify the correct proportion

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Scales and similar shapes

7.5C - solve mathematical and real-world problems involving similar shape and scale drawings

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2023-4: a scale was given, students had to find a related estimate

2024-1: a scale was given, students had to find a related estimate

2024-19: similar shapes were given, students had to find the length of one side

2025-10: a scale was given, students had to find a related estimate

2025-20: similar shapes were given, students had to find the length of one side

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Probability

7.6D - make predictions and determine solutions using theoretical probability for simple and compound events

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2025-6: a spinner was shown, students had to predict how many times it would land in certain spaces