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Glacius
FoundationsConcept reference

Signed numbers

An integer is zero or a positive or negative whole number, with its sign distinguishing nonzero positions on opposite sides of zero.

1 min read2 figuresSources & further reading
On this page 9 sections
  1. Overview
  2. Integers are zero and positive or negative whole numbers
  3. Check your understanding
  4. Check your understanding
  5. Check your understanding
  6. Key takeaway
  7. Further questions
  8. Sources & further reading
  9. Concept connections

01Integers are zero and positive or negative whole numbers#

Integers are zero and positive or negative whole numbers. A reading of −4 ∘C-4\,{}^\circ\mathrm{C} means four degrees below zero.

On a horizontal number line, −4-4 sits four equal unit intervals left of zero.

A horizontal number line has equal unit intervals from negative five to positive five, with zero in the center. Negative values are left of zero and positive values are right. Negative four is marked four intervals left of zero.A horizontal number line has equal unit intervals from negative five to positive five, with zero in the center. Negative values are left of zero and positive values are right. Negative four is marked four intervals left of zero.
Figure 1A horizontal number line has equal unit intervals from negative five to positive five, with zero in the center. Negative values are left of zero and positive values are right. Negative four is marked four intervals left of zero.
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Positive numbers are right of zero. The labels +4+4 and 44 mean the same number.

Both −4-4 and +4+4 are four units from zero, on opposite sides.

A horizontal number line has equal unit intervals from negative five to positive five, with zero in the center. Negative values are left of zero and positive values are right. Negative four and positive four are marked, each four intervals from zero on different sides.A horizontal number line has equal unit intervals from negative five to positive five, with zero in the center. Negative values are left of zero and positive values are right. Negative four and positive four are marked, each four intervals from zero on different sides.
Figure 2A horizontal number line has equal unit intervals from negative five to positive five, with zero in the center. Negative values are left of zero and positive values are right. Negative four and positive four are marked, each four intervals from zero on different sides.
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Check your reasoning

Is 00 positive or negative?

  1. APositive
  2. BNeither
  3. CNegative
Show answer and explanation
Neither

Zero is neither positive nor negative. It is the reference itself.

02Check your understanding#

Check your reasoning

On a horizontal number line, which label is three units left of zero?

  1. A33
  2. B−2-2
  3. C−3-3
Show answer and explanation
−3-3

Left is negative. Three units from zero gives −3-3.

03Check your understanding#

Check your reasoning

Street level is 00; above is positive. Where is floor −2-2?

  1. ATwo floors below
  2. BTwo floors above
  3. CStreet level
Show answer and explanation
Two floors below

Minus means below street level; 2 counts the floors.

04Check your understanding#

Check your reasoning

A robot marks its start as 00 and right as positive. What position is six units left of its start?

Show answer and explanation
-6

Right is positive, so left is negative. Six units left of zero is −6-6.

Key takeaway

Read the sign and the distance from zero together.

  • Read a signed integer as a position relative to zero.

Further questions

Why is the plus sign sometimes missing?
For a positive number such as 4, the plus sign is optional: 4 and +4 name the same value. Zero is still neither positive nor negative.

Sources & further reading

  1. [1]

Reference this concept

Link to this page, a section, or an individual figure.

Glacius. “Signed numbers.” Math behind ML. /learn/f-signed