(computer – Online Book) 1.3 Subtracting Integers (computer – Online Book)
Subtracting Integers “adding the opposite” Steps 9 – 12 keep the 1st number 9 change – to + 9 + change 2nd number to opposite 9 + (–12) follow addition rules –3 (keep, change, change) Use “Counters” & check with “Number line”.
Simplify 2 – 7 2 + (–7) – 5 (keep, change, change) Use “Counters” & check with “Number line”.
Simplify –5 – 2 –5 + (–2) – 5 (keep, change, change) Use “Counters” & check with “Number line”.
Simplify 15 – 23 15 + (–23) – 8 (keep, change, change) Try it!
Simplify –14 – (–18) –14 + 18 4 (keep, change, change) Try it!
Simplify 5 – (–14) 5 + 14 19 (keep, change, change) Try it!
Simplify –4 – 6 – (–13) –4 + (–6) + 13 –10 + 13 3 (keep, change, Try it!
Simplify –7 – (5 – 8) –7 – (5 + (–8)) –7 – (–3) –7 + 3 – 4 Try it!
Simplify │–12│ – 20 12 – 20 12 + (–20) – 8 Try it!
Evaluate │a│ – │b│ for a = –7 and b = –8 │–7│ – │–8│ 7 – 8 7 + (–8) – 1 Try it!
Sample Application Problem (Please refer to Textbook Example 3 on p.17)
Homework p.18 3,4-48 even, 55 Quiz 1.1 to 1.3 (MC #7,8,9)