有理数的加法7

1、1()2?imsu ?81?: ?悠 ?悠re悠d ?1? ?rral? ?”1+“ 悠? ?1悠ia?悠a ?1? ?rral “-1” ?1?1t ?1浔?1?1a悠? . ? ?tt1d ?t1rlt ?r1a1悠 ?a1t1ra吾a 悠iia?悠a ?1el?: ?1i悠 悠t悠a ?a?悠l1a ?浔?1? ?1r1?e?t?i ?r1?1? ?rlt ?1? ?al? 悠 ?悠re悠d ?r1tt1d ?rlt ?1? ?al? 悠 ?1?悠ia?悠a. ?1i悠 ?1r1t悠a ? ?tt1d ?t1rlt ?a1悠 浔?r悠t ?al (+1)+(-1)=03 ?浔浔d ?1i

2、悠 悠t悠a ?a?悠l1a ?浔?1? ?1r1?e?t?i ?r1?1? ?rlt ?1? ?al? 悠? ?1悠ia?悠a ?r1tt1d ?rlt ?1? ?al? 悠 ?悠re悠d ?悠ael? ?1i悠 ?1r1t悠a ? ?tt1d ?t1rlt ?a1悠 浔?r悠t ?al? aa?l? (-1)+(+1)=01浔r? ?1?1t?悠d 1 + ?r ? 1浔r? ?1?1t?悠d 1 ?r ?浔a1?1悠1d ?d?r?ta悠 悠ael? 0?r 悠ael? 0?r ?浔?1悠1d. ?imsu ?81?:4 (1)?r1t1ra吾a ?a?悠a: ?1i悠 悠t悠a ?a?

3、悠l1a ?浔?1? ?r?e?t?i ?r1?1? ?rlt 2 ?al? 悠? ?1悠ia?悠a ?r1tt1d ?rlt 3 ?al? 悠? ?1悠ia?悠a. ?1i悠 ?1r1t悠a ? ?tt1d ?t1rlt ?a1悠 浔?r悠t ?al (-2)+(-3)5 (-2)+(-3)_= -5?m8 ?m?:6 (2) (-3)+2_= -1?悠ra1 ?悠t悠?:7 (3) 3+(-2)_= 1?悠ra1 ?悠t悠?:8 (4) (-4)+4_= 0?悠ra1 ?悠t悠?:9?悠ra1 ?悠t悠?: (1)(-2)+(-3)=0 1 2-1-2-3-4-5-510?悠ra1 ?悠t

4、悠?: (2) (-3)+2=0 1 2-1-2-3-4-5-111 (3) 3+(-2)=0 1 2-1-2-331?悠ra1 ?悠t悠?:12?悠ra1 ?悠t悠?: (4) (-4)+4=0 1 2-1-2-3-4-5013(1)(-2)+(-3)=-5(2)(-3)+2=-1(3)(+3)+(-2)=1(4)(-4)+4=0 ?tt1d ?悠rldaa? ?rr悠a ?悠d?d ?r悠iilt ?1r1r1r1 ?a1?悠d ?r悠t ?1r1?1橔e浔? ?1r1r1r1? 浔?a? ?a11t ?r悠t ?1r1?1橔e浔? ?1? ?悠a ?浔?1? 0 ?1r ?a1r1r1

5、浔?r悠t ?1el?ald ?1i?.14 ?1? ?1? ?1?a浔?悠d ?tt1d ?rr悠a ?悠d?d ?r悠iilt 浔橔1t11?a浔d ?悠i?ld ?浔?悠d ?1r1?d ?浔?a? ?1?a浔1t ?悠d?ld ?1e?ilt. ?浔?a? ?1?a浔1t ?浔a ?悠r1el? ?浔 ?1? ?1?a浔?悠d ?tt1d ?rr悠a ?悠d?d ?r悠iilt ?浔?a? ?a11t ?l? ?1rr悠a ?a1?悠d ?1r1?d ?al? ?浔?a? ?1aa浔1t ?a?t1?1t ?浔?a? ?浔1t ?1r1?d . ?i?悠t?1?悠t ?1r?ar悠a ?a1r1r1? 0 1el?. ?1? ?悠a ?浔?1? 0?1r ?a1r1r1? i ?1rr悠a 浔橔1?d ?浔a.?悠rld1aa? ?r?ar悠a ?ilt ?a11d悠t15?r?浔?1t1ra吾a ?aaa?悠a:(1) 180+(-10) (2) (-10)+(-1) (3) 5+(-5) (4) 0+(-2) ?浔?i1d ?1i?16?r?1a1r? ?悠r1a ?1i? (+5)+(-2)=-7 (