Math · Grades 5–6 and 7–8
Below zero
Your child reads and moves through numbers below zero the way a lift, a thermometer and a diver do.
Your child moves a marker on a lift shaft, a thermometer, the sea and a pretend balance, and answers questions across zero. If an answer is wrong, the game says which mistake it was.
- Grades 5–6 and 7–8
- 15 min
- Nothing to prepare
- On the screen
Free to sign up.
Is it a good fit?
- Ready if Your child adds and takes away whole numbers on a number line.
- Too much today? Start with How many do you think?: one number line, every number above zero, before the line carries on below it.
- Too easy? The Grade 7–8 level: adding and taking away across zero, a rate going down, the mean of cold nights, and taking away a debt.
What your child practises
- Numbers below zero
- Comparing them
- Moving across zero
- Adding, taking away and multiplying them
“Down 5 from 2: two to the street, then three more. B3.”
If your child says something like this, in their own words, the idea has landed. Finishing the rounds means they took part; this is the learning.
Your part
- Nothing for the game itself
- Each question has a Read it to me button
Take it off the screen (optional)
Read the freezer's thermometer together, and the floor buttons in a lift with floors under the street, out loud with their signs.
More like this
The full design
What it is
Below zero is the number line carrying on. A lift goes down past the street to B1 and B2, a freezer reads −18°, a diver swims below sea level, and money owed is below nothing. It is really about integers: placing them, comparing them, moving across zero, and at the top adding, taking away and multiplying them.
How it goes
The number line stands up beside the question: a lift shaft, a thermometer, the sea against a cliff, or a column of having and owing. Your child moves the marker with the buttons or a tap on the line and checks. When it is not right the game says which mistake it was: the right number on the wrong side of zero, the wrong way, stopping before zero, or how far off. Some rounds are a question with three answers to pick from. Four places make a game.
The Pet
It asks which way first and how far to zero, and notices when a move went past zero cleanly. The money is the Pet's: it borrows from a friend for a kite and pays it back. Its dare is the next step up: at 5–6, three lift moves in a row; at the top, the coldest it got where you live this winter and how far it fell.
By band
One play is four places, easiest first: the lift, the freezer, the diver and the money borrowed. 5–6: where the lift stops after going down 5 from floor 2, which of −3° and −8° is colder, how far below the surface, and a balance after borrowing and paying back. 7–8: the floors from B3 to 6, three moves in a row, a freezer warming 3° every 10 minutes, how far a night's temperature fell across zero, the mean of four cold nights, the distance from a diver to a gull, twice as deep, and taking away a debt.
What it grows
The standards place numbers below zero on a line, a thermometer, sea level and money owed before they ask for arithmetic with them (Common Core 6.NS.C, then 7.NS.A). The game's line stands up because the places do: down already means less.
Done, and what counts as evidence
Done means the four places answered right. "Counted to zero first when a move crossed it" is an observation you may keep. The best record is off the screen: the freezer's thermometer or a lift's buttons read out loud with their signs.
What's personal
The thermometer is in your family's scale, °C or °F, with its freezing line where it really is (32 on °F); depths are in metres or feet; the money is in your currency. The money is pretend: nothing is bought or paid.