Double negative
Removing a debt is the same as gaining money: −(−3) = +3.
Why it works
Cancelling a $3 charge leaves you $3 richer.
Integers · Subtract integers · 5.4
Minus a negative.
Subtracting a negative is adding a positive: the two minus signs combine into a plus. 5 − (−3) = 5 + 3 = 8.
See it work.
Zero pairs
A +1 and a −1 cancel.
5 − 3 = 5 + (3)
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Watch the method
Minus a negative
5 − (−3) = 5 + 3 = 8.
1
Add the opposite
Subtracting is adding the opposite: change − to + and flip the sign of (-3).
2
Same sign — add the sizes
Both are positive, so add their sizes: 5 + 3.
3
Keep the sign
Both positive → the answer is positive.
Practice until it feels automatic.
Your turn
Work it out.
Type a whole number — negatives allowed, e.g. -7.
streak 0
best 0
… =
The idea underneath.
From easy to tricky.
Subtract 5 - -4
1
Add the opposite
Subtracting is adding the opposite: change − to + and flip the sign of (-4). 5 - (-4) = 5 + 4
2
Same sign — add the sizes
Both are positive, so add their sizes: 5 + 4. 5 + 4 = 9
3
Keep the sign
Both positive → the answer is positive. 5 + 4 = 9
Subtract -10 - -3
1
Add the opposite
Subtracting is adding the opposite: change − to + and flip the sign of (-3). -10 - (-3) = -10 + 3
2
Different signs — subtract
Subtract the smaller size from the larger: 10 − 3. 10 - 3 = 7
3
Take the bigger sign
10 is the larger size and it is negative, so the answer is negative. -10 + 3 = -7
Subtract -12 - -5
1
Add the opposite
Subtracting is adding the opposite: change − to + and flip the sign of (-5). -12 - (-5) = -12 + 5
2
Different signs — subtract
Subtract the smaller size from the larger: 12 − 5. 12 - 5 = 7
3
Take the bigger sign
12 is the larger size and it is negative, so the answer is negative. -12 + 5 = -7
Where students slip.
Trap
Leaving it as 5 − 3.
Fix
Two minuses make a plus: 5 + 3.
Trap
Only changing one of the two signs.
Fix
The operation and the sign combine to +.
Test yourself.
The Test
12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.
0/12Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so
t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).Core
Core (4)
C1
Subtract 5 - -4
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
C2
Subtract -4 - -8
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
C3
Subtract 8 - -10
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
C4
Subtract -1 - -11
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
Apply
Apply (4)
A1
Subtract -10 - -3
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
A2
Subtract -6 - -9
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
A3
Subtract -11 - -2
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
A4
Subtract 9 - -12
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
Extension
Extension (4)
E1
Subtract -12 - -5
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
E2
Subtract 4 - -12
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
E3
Subtract 5 - -2
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.
E4
Subtract -10 - -10
Need a hint?
- Two minuses make a plus.
- Rewrite −(−3) as +3.