# Worksheet: Opposite Number

Q1:

A chemistry teacher told his students that at ion is an atom that has an unequal number of electrons and protons, and that all ions have a charge. A negative charge means that the ion has more electrons than protons. A positive charge means that it has less electrons than protons.

 Ion Charge Oxygen Chlorine Aluminum Magnesium Potassium − 2 − 1 + 3 + 2 + 1

Which ion in the table has a charge that is not the opposite of the charge of one of the other ions?

• Apotassium
• Bmagnesium
• Cchlorine
• Daluminum
• Eoxygen

Q2:

In Yakutsk, the temperature in February is . A weather forecast predicts that a warming trend will increase the temperature to . If the temperature increases with an average of per week, how many weeks will it take to reach ?

Q3:

The normal low temperature during January for a town in Alaska is . Isabella represented this temperature with a number on a number line. If you plotted the opposite of that number on the number line, between which two integers would it lie?

• A and
• B and
• C9 and 10
• D8 and 9
• E and

Q4:

This is a player’s scorecard after 5 holes in a golf championship.

 Hole Par Your Score 1 2 3 4 5 6 7 8 9 5 4 3 3 4 3 4 3 5 7 3 4 3 4

Given that they were on par at the end of the ninth hole, which of these could have been their scores for the last 4 holes?

Note: To be on par, the sum of the scores must be equal to the sum of the par values.

• A3, 2, 3, 4
• B3, 3, 5, 4
• C3, 3, 3, 5
• D3, 3, 3, 4
• E2, 2, 3, 5

Q5:

In a game, the white counters count as and the blue counters count as . Pick the move that would result in a total score of zero.

• Asubtract two white counters
• Badd one blue counter
• Cadd two blue counter
• Dadd one white counter
• Esubtract two blue counters

Q6:

One of addition’s properties is that the sum of a number and its opposite is always equal to zero. Which of the following situations does not demonstrate this property of addition?

• AOn a Sunday, the temperature was outside and inside.
• BThe school’s football team lost 5 yards on their first down and gained 5 yards on the second down.
• CA ball was kicked 10 m upward in the air, and then it fell down 10 m.
• DThe school’s football team lost 10 yards on their first down and lost 10 yards on the second down.
• EA bucket descended 100 m down a well, and then it was lifted 100 m up the well.

Q7:

Two hot air balloons were flying at the same height. Then, Balloon A ascended 15 feet, while balloon B descended 15 feet. If we represent these changes by integers, will they sum to zero?

• Ayes
• Bno

Q8:

Michael flies a helicopter from a point 10 feet below sea level to a point 10 feet above sea level.

Which integer represents his starting elevation?

Which integer represents his finishing elevation?

What can you say about these integers?

• Athey are the same
• Bthey are opposites

Q9:

Natalie, Ethan, Mason, Emma, and Charlotte play a question-and-answer game. A player steps forward for each correct answer and steps backward for each incorrect answer. During the first round, Emma takes four steps backward, Natalie takes five steps forward, Ethan takes five steps backward, Charlotte takes four steps backward, and Mason does not move. Which two players moved in opposite directions but are the same distance from the starting point?

• ANatalie and Mason
• BCharlotte and Emma
• CCharlotte and Mason
• DNatalie and Ethan
• EEmma and Ethan

Q10:

Determine the two integers where the first is the opposite of , the second is greater than the first, and the difference between both is 26.

• A ,
• B ,
• C ,
• D ,
• E ,

Q11:

Sophia plays the same game for 15 minutes every day. On Sunday her score was . On Monday she gained 15 points, on Tuesday she gained 25, and on Wednesday 10. If her score at the end of Thursday was 0, write an integer to represent the points she gained or lost that day.

Q12:

The table shows the scores that ten teams received in a competition. Name two teams whose scores are additive inverses of each other.

 Team Score A B C D E F G H I J +4 0 +3 − 7 − 3 +6 − 8 − 2 +1 +9
• AA and B
• BC and D
• CB and I
• DC and E
• EI and J

Q13:

The table shows four friends’ golf scores.

 Player Score Ethan Liam Noah Michael − 2 9 − 5 4

What integer is the opposite of Liam’s score?

Q14:

Sophia’s account had a balance of . She then made a deposit of \$50.25. Is the balance in her account now 0?

• Ano
• Byes

Q15:

The opposite of is , and their sum is zero.

Q16:

What is the additive inverse of 0?

Q17:

The table shows the average recorded temperature over four days.

 Day Temperature Monday Tuesday Wednesday Thursday 6 degrees below 0 3 degrees above 0 3 degrees below 0 0 degrees

If we plotted these temperatures on a number line, which two days would be the same distance from zero?

• AMonday and Wednesday
• BMonday and Thursday
• CTuesday and Monday
• DTuesday and Wednesday
• EThursday and Wednesday

Q18:

How can a point 75 m above sea level be represented as an integer?

• A75
• B

Q19:

In an atom, protons have a charge of , electrons have a charge of , and the charge of an atom is the sum of the charges of its protons and electrons.

A sodium atom has 11 protons and 11 electrons. Does it have a zero charge?

• Ayes
• Bno

Q20:

How can a point 125 m below sea level be represented as an integer?

• A
• B125