Numbers & Operations
Subtracting Numbers
To subtract any number, use Keep · Change · Change (KCC): keep the first number, change subtraction to addition, change the sign of the second number. Then follow the addition rules.
Visualize It
The Golden Rule: Keep · Change · Change
KEEP
Keep the first number exactly as it is
−5
CHANGE
Change subtraction ( − ) to addition ( + )
−
CHANGE
Change the sign of the second number
+3 → −3
Then just follow the addition rules you already know!
Example 1 — 6 − (−4)
After KCC: both positive → add and keep positive → 10
Example 2 — −5 − 3
After KCC: both negative → add and keep negative → −8
Example 3 — −8 − (−2)
After KCC: different signs → subtract, keep sign of bigger (8) → −6
Every Subtraction Becomes Addition — Then Use These Rules
Watch & Learn
Watch a clear, friendly video explanation of Subtracting Numbers:
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Worked Examples
Follow along with these step-by-step examples. Take your time — there's no rush!
Problem
Calculate: 6 − (−4)
Step-by-Step Solution
Keep the first number: 6
Change subtraction to addition: 6 +
Change the sign of −4 to +4: 6 + 4
Now add: both positive → add and keep positive.
6 + 4 = 10
Answer
10
Problem
Calculate: −5 − 3 (both negative after KCC)
Step-by-Step Solution
Keep: −5
Change subtraction to addition: −5 +
Change the sign of +3 to −3: −5 + (−3)
Now add: both negative → add and keep negative.
5 + 3 = 8, so the answer is −8.
Answer
−8
Problem
Calculate: −8 − (−2) (different signs after KCC)
Step-by-Step Solution
Keep: −8
Change subtraction to addition: −8 +
Change the sign of −2 to +2: −8 + 2
Now add: different signs → subtract, keep sign of the bigger (8 is negative).
8 − 2 = 6, so the answer is −6.
Answer
−6
Problem
Calculate: 4 − 11 (result is negative)
Step-by-Step Solution
Keep: 4
Change subtraction to addition: 4 +
Change the sign of +11 to −11: 4 + (−11)
Different signs → subtract: 11 − 4 = 7.
The larger absolute value (11) is negative, so the answer is −7.
Answer
−7
Problem
Calculate: −12 − (−12) (cancel out)
Step-by-Step Solution
Keep: −12
Change subtraction to addition: −12 +
Change the sign of −12 to +12: −12 + 12
Different signs, equal absolute values → they cancel out.
Answer
0
Your Turn — Practice Problems
Try all 5 problems on your own first. Write out your work — that's how it sticks!
💡 Tip: Don't peek at the answers until you've genuinely tried each one.
9 − (−5)
−4 − 7
−3 − 10
0 − (−6)
−15 − (−15)
7 − 20
−8 − (−3)
12 − (−4)
−1 − 1
0 − 9
−20 − (−5)
6 − 6
Finished all 12? Give yourself a pat on the back — then check your work!
Keep going — you're on a roll!
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