---
title: "Negative Numbers Across Zero"
description: "Use negative numbers in context (temperature, finance, sea level); calculate intervals across zero"
canonical: https://lightmysky.com/learn/mathematics/negative-numbers-across-zero-mt_RVK655t391
source: https://lightmysky.com/learn/mathematics/negative-numbers-across-zero-mt_RVK655t391.md
retrieved: 2026-09-12
---

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# Negative Numbers Across Zero

Use negative numbers in context (temperature, finance, sea level); calculate intervals across zero

Subject: Mathematics · Area: Number Representation & Place Value · Ages 10 to 11
Page: https://lightmysky.com/learn/mathematics/negative-numbers-across-zero-mt_RVK655t391

## Ready when they can

- The temperature falls from 3°C to −5°C — what is the drop? (8 degrees)
- Calculate the difference between a bank balance of −£120 and £350
- Order −7, −3, 0, 2, 5 on a number line and find the interval from −7 to 5

## Lesson: Measuring the gap across zero

You already know that temperatures, bank balances, and sea levels can sit below zero. Now it's time to measure the change between two readings. Count the distance from the start down to zero, then the distance from zero up to the end, and add the two together.

*(drawing: The temperature falls from 3°C to −5°C: 3 degrees down to zero, then 5 more. That's a drop of 8.)*

**Example.** Jay's savings account shows −£120. After a birthday gift, it shows £350. From −£120 to £0 is a change of £120. From £0 to £350 is another £350. £120 + £350 = £470, so his balance changed by £470.

**Tip.** When you cross zero, add the two distances instead of subtracting. Crossing from below zero to above zero (or back) always makes the gap bigger than either number alone.

**Recap.** To measure a change across zero, add the distance down to zero and the distance up from zero.

## Practice

14 questions on this page, each with its working shown.

## Needs first

- [Negative numbers in context](https://lightmysky.com/learn/mathematics/negative-numbers-in-context-mt_1KkvzwYxbR)

## Opens up

- [Positive and Negative Numbers](https://lightmysky.com/learn/mathematics/positive-and-negative-numbers-mt_9QzSnn8m80)
- [Linear number sequences](https://lightmysky.com/learn/mathematics/linear-number-sequences-mt_hBZwbst0ow)
- [Coordinates (age 10+)](https://lightmysky.com/learn/mathematics/coordinates-age-10-mt_R4AY0LKxfl)
- [Numbers to Ten Million](https://lightmysky.com/learn/mathematics/numbers-to-ten-million-mt_XNmGwNggdU)