1、 =571+1 =572第十一种178X101-178 83X102-83X2 17X23-23X7 35X127-35X16-11X35 =(101-1)X178 =100 X178 =17800第十二种 64(8X2) 1300(13 X5) 480(8 X2) =6482 =8 =4第十三种 62525 36024 27045 =6255 =125 =25 第十四种100+45-100+45 25+75-25+75 423+76-76+77 243+85-243+85 =(100-100)+(45+45) =0+90 =90第十五种20X420X4 25X425X4 56X856X8 1
2、2X612X6 =(2020)X(4X4) =1 X 16 =16 练习:169+354+231+146 987-362-138 1347-(347+125)135+236-135+236 198 X26 148 X56-48 X56 21015 199 X37+37 215 X63-15 X63 101 X22-22 203 X14 125 X33 X4 125 X16 X50 365+997 452-398 简便运算习题1.加法交换律(a+b=b+a)如:152+389+348=152+348+399=500+399=899习题:77+56+23 165+477+135 154+288+4
3、62.加法结合律a+b+c=a+(b+c)591482118=591(482118)=591+600=1191285+147+253 99+178+122 456+588+412 692+325+753.加法交换律、结合律32296841 =32+68+29+41 加法交换律 =(32+68)+(29+41) 加法结合律 =100+70 =170(148+64)+(52+136) 650+(171+350)+129 128+114+86+1724.乘法交换律ab=ba25454 =254 =10045 =4500314 125278 4069255.乘法结合律:abc= a(bc)781258
4、 12532 =78(1258) =125(84)1000 =12584 =78000 =40005272 12588 2532 2544 125486.乘法交换律、结合律25 =12525 乘法交换律=(1258)(425)乘法结合律=1000=10000032 7.乘法分配律:(b+c)=ab+ac57+2743 2799+27 27 99 =27(57+43) =27(99+1) =27(100-1)100 =27100-271 =2700 =2700 =26736734+6766 12743-27101-27 27 101 6721+6778+67 6723+6778+67-67123
5、40+66120 2585102 69102 789865+6599 587+87+878.减法运算性质; a-b-c=a-(b+c)=a-c-b781-178-122 721-488-121 745-(245+188) =781-(178+122) =721-121-488 =745-245-188 =781-300 =600-488 =500-188 =481 =112 =312 456-273-127 623-169-223 553-(289+153 ) 772-456+228 689-(289-153 ) 136-88+164-1129.除法运算性质;a b c=a c)=a c b7
6、20 36 2 =720( 36 2) =720 72 =1027004 560056 3900 (39 综合练习简便运算怎样简便就怎样算。一、355+260+140+245 98101 48125 645-180-245389938 3500145 175562556 502040二、368+156+344+132 125478 72004 449658+9642 6300(635) 482 -(182+50) 13527+13572+135三、368+156+344+132 125四、789-136-64 13229+132 9883+166 3700881250 48125 125321
7、25 3688+3615-108五、355+260+140+245 98125 645-180-245 56 125六、98+265+202 273-73-27 250134 3200125 9938+38 1723-237 72125七、6415-564 25(1240) 9956+56 21821655345 320025 29899298 (408)25 97八、355+260+140+245 10299 2382101-382 460508 358+356-435 125九、2546 10156 9926 1022478422987(287135) 478256144 6723664
8、36643664十、48728713961 50025734143 2000368132 1814378422899989 1552643644 25(204) 8822522512 十一、6982919 568(68178) 5611958 3821653582 236+189+64 759-126-259794 569-256-44 十二、216+89+11 5781050157 169123231693799+37 129101129 14969149+14932 5651+5648+56十三、125 2425 12548 514+189214369256+15612573+2624 1
9、09+(291176)十四、1698+32 512+(373212) 228+(72+189) 169+199 58699 575250275 3721211221 125三、计算(能简便就简便) 一、85+14(14+20826) 21+(327-23)19 539-513(37814) 34-30941713 19+(253-22)21 50+2028-42 (23+23)24-597 (110-10)10-10 45-24+1414 二、304-275(27525) (70+10)(18-10) 12018-54 44+1615-32 (10-10010)11 (53-58821)36
10、(60+10)(17-10) 17+(233-43)10 1001010-60 三、424-4751916 22+(374-10)26 (245-11)18-11 22-(10+10010) (252-14)17-10 35-13+1015 (346-10)16-12 215-198(12111) (45-65133 四、19+19212-10 5722223-158 19+56-122434 (714-12)27-19 14+(21-19)14 18-(13+15)262 736(43-20)23 (227+11)(31-14) 36+1914-23 五、8282312-48 18-15+1
11、018 (31-15411) (1369-37)37-32 160(22-12)22 3572113-213 985-7282635 (438-39)21-12 (20+18)11-239 六、5016040 (58+370)(64-45) 120-14418+35 50144012 385616+8516 4000(16+83213)(326+9525)37 (723618228)28 (42752475)七、178-14556+42 420+580-642128 812-700(9+3111)5016040=54 120-14418+35=147 (58+37)(64-95)95(64-4
12、5) 178-1456+42 120-3618+35八、58585842 3874(8741000) 136101-1363293862 347129147 460060008 2532 360九、4425 591482118 99I26158 986+1999 473+79-6380501-80 76+38+24+162 19999+199 十、2598 5525+2532+129+268+71 438+126+162+674 5555+455565 8135+865 5637-5626-56十一、4512+5512 429+589 5545+451827+1823 58137-5837 7
13、88-288 769+721 3627+2764 9964+64十二、25036 48250 20232 19950 30130201-45 4949+49 25(8+40)十三、8125 7250 250359+931 899+9999199+99 35401-35 39101-39 十四、25125 15(4+164) 165-35-65943810662 12548 98918614 十五、46004 136101136 3237473721377777 998 7837376899+125)16 5999+5+997+7+39+3+9 十六、355+260+140+245 10299 645-180-245 38235
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