L1 · Adding integers

Learning goal

“I can add any two integers quickly and reliably - including two-digit numbers - by comparing magnitudes: same signs, add the magnitudes and keep the sign; different signs, cancel zero pairs and keep the sign of the bigger magnitude.”

Integer — a whole number that can be positive, negative, or zero.

Magnitude — a number's distance from zero: the magnitude of -64 and of 64 is 64. Magnitude ignores the sign.

Zero pair — one positive and one negative counter, worth 0 together - still the adding tool underneath every rule.

Sum — the result of an addition.

Worked example

Add -38 + (-17). Step 1: Both addends are negative. On the number line, start at -38; adding a negative moves LEFT 17 more: you end further from zero on the negative side. Step 2: Counters agree: 38 negative counters plus 17 more negative counters is 55 negative counters. Step 3: Strategy: same signs - add the magnitudes (38 + 17 = 55) and keep the shared sign: -38 + (-17) = -55. Say it plainly: when both numbers pull the same way, the distance from zero grows.

Check yourself — explain it

-38 + (-17) is negative because...

Paired problem — example still visible

-42 + (-18) -> magnitudes 42 + 18 = 60, sign negative: -60

Faded completion — last step is yours

"-57 + (-25): magnitudes 57 + 25 = 82, sign stays ___, so the sum is ___." -> negative; -82

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

Start practice →Take the unit quiz