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ALGEBRA1
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CHAPTER2.2T
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1994-02-15
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à 2.2ïThe addition operation on signed numbers.
äïPlease add the following numbers.
â
êêêêè 5 + 3 =8
êêêê -6 + (-3) = -9
êêêêï7 + (-4) = 3
êêêêï-6 + 2 = -4
éS
To add two numbers that have the same sign, just add the two numbers and
take the sign that they have in common.ïThe numbers 5 and 12 have the
same sign since they are both positive.ïTheir sum is therefore plus
seventeen, ieï5 + 12 = 17.èThe two numbers -8 and -6 have the same
sign and their sum is negative fourteen, ie -8 + (-6) = -14.
Parençs are used around the negative six for clarity.
To add two numbers with unlike signs, just subtract the smaller from
the larger and take the sign of the larger.ïThe two numbers -6 and 9
have unlike signs.ïTheir sum is found by subtracting the smaller from
the larger (9 - 6 = 3) and attaching the sign of the larger (-6 + 9 = 3)
The two numbers -8 and 4 have unlike signs.ïThe smaller from the larger
is four and the sign of the larger is negative.ïThus their sum is
negative four. (-8 + 4 = -4)
1
êêêêë7 + 4
êë A)ï3êB)ï11êC)ï-3êD)ï-11
ü
êêêêè7 + 4 = 11
Ç B
2
êêêêè-8 + (-9)
êë A) -1êB) 17ê C) 1êïD)ï-17
ü
êêêë -8 + (-9) = -17
Ç D
3
êêêêè-12 + 8
êë A) -4êB)ï20êC)ï4ê D)ï-20
ü
êêêê -12 + 8 = -4
Ç A
4
êêêêè6 + (-11)
êê A)ï5ë B)ï17ë C)ï-17ëD)ï-5
ü
êêêê6 + (-11) = -5
Ç D
5
êêêê6.8 + (-17.1)
êëA) -23.9êB) -10.3ë C) 10.3ë D) 23.9
ü
êêêè6.8 + (-17.1) = -10.3
Ç B
6
êêêë -14.7 + (-3.2)
êïA) -17.9êB) 11.5êC) -11.5êD) 17.9
ü
êêêï-14.7 + (-3.2) = -17.9
Ç A
7
êë 2è┌ï1 ┐êê5êï11ê 5ê 11
êë ─ + │- ─ │ê A) - ──è B) - ──è C) ──ëD) ──
êë 3è└ï4 ┘êë 12êï12ê12ê 12
ü
êêë2è┌ï1 ┐ë 8è┌è 3 ┐ë 5
êêë─ + │- ─ │ï=ï── + │ - ── │ï=ï──
êêë3è└ï4 ┘ë12è└è12 ┘ë12
Ç C
8
êë 1ë 3êë16ê 31ê16êè7
êè 2 ─ï+ 1 ─ê A)ï──è B)ï──è C) ──ëD) 3 ─
êë 2ë 8êë 8ê 16ê10êè8
ü
êë1ë 3ë 5è11ë 20è 11ê31ê 7
êè2 ─ï+ 1 ─ï=è─ + ──ï=è──ï+ ──è=è──ï=è3 ─
êë2ë 8ë 2è 8ê8ë8ê 8ê 8
Ç D
9
êêêê-2 + [5 + (-3)]
êë A) -3êB)ï7ê C)ï0ê D)ï-1
ü
êêë -2 + [5 + (-3)] = -2 + [2] = 0
Ç C
10
êêêê[-7 + (-5)] + 8
êë A)ï6êB) -4ê C) -6ê D)ï20
ü
êêè [-7 + (-5)] + 8ï=ï[-12] + 8 = -4
Ç B
11
êêêï[-6 + (10)] + [8 + (-6)]
êëA)ï6êB) -12êC) -6ê D)ï14
ü
êê[-6 + (10)] + [8 + (-6)]ï=ï[4] + [2]ï=ï6
Ç A
12
ï┌ï3è 4 ┐ë┌ 2è ┌è5 ┐ ┐ê 3ê 1êï5ê5
ï│- ─ï+ ─ │ï+ï│ ─ï+ │ - ─ │ │ëA) ─è B) ──è C) - ─è D) ─
ï└ï8è 8 ┘ë└ 4è └è4 ┘ ┘ê 8ê24êï8ê8
ü
┌ï3è 4 ┐ë┌ 2è ┌è5 ┐ ┐ë┌ 1 ┐è┌ï3 ┐è 1è┌ï6 ┐ë 5
│- ─ï+ ─ │ï+ï│ ─ï+ │ - ─ │ │ï=ï│ ─ │ + │- ─ │ =ï─ + │- ─ │ =ï- ─
└ï8è 8 ┘ë└ 4è └è4 ┘ ┘ë└ 8 ┘è└ï4 ┘è 8è└ï8 ┘ë 8
Ç C