A student is learning about positive and negative numbers with manipulatives. Each black cube represents + 1 , and each white cube represents − 1 . If there are currently 15 black cubes on the student's desk, how many white cubes must the student add to the desk for the combined value of the cubes to represent 0 ?

Question

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MrRoyal MrRoyal · Answer 1 · 2020-11-20T02:48:14+01:00

Answer:

15 white cubes

Step-by-step explanation:

Given

[tex]White\ Cubes = -1[/tex]

[tex]Black\ Cubes = +1[/tex]

[tex]Number\ of\ Black\ Cubes = 15[/tex]

Required

Determine the number of white cubes needed to represent 0

To solve this question, we make use of the following equation.

[tex]Black\ Cubes +White\ Cubes = 0[/tex]

If there are 15 black cubes, the the 15 black cubes is worth: +1 * 15

Substitute +1 * 15 for the Black Cubes

[tex]+1 * 15 +White\ Cubes =0[/tex]

[tex]+15 +White\ Cubes =0[/tex]

Collect Like Terms

[tex]White\ Cubes = 0 - 15[/tex]

[tex]White\ Cubes = - 15[/tex]

Recall that 1 white cube is worth -1

So, the number of white cubes is:

[tex]Number = \frac{-15}{-1}[/tex]

[tex]Number = 15[/tex]

Hence, the student needs 15 white cubes