Giải đáp án $D.~a,~(\frac{--}7-\frac15)-[\frac12-(-\frac27-\frac2{10})].$ $b,~8\frac13+0,25+\frac12-(3,5+2\frac13-\frac34).$,i 7: Tính: $A=7+(\frac7{12}-\frac12+3)-(\frac1{12}+5)$,i8: ínnh $A=\frac{-1}4+\frac7{33}-\frac53-(-\frac{15}{12}+\frac6{11}-\frac{68}{49})$,i 9: Tính: $A=(3-\frac14+\frac23)-(5-\frac13-\frac65)-(6-\frac74+\frac32).$,i 10: Tính: $A=(6-\frac23+\frac12)-(5+\frac53-\frac32)-(3-\frac73+\frac52).$,i1: Tính: $A=(\frac53-\frac37+9)-(2+\frac57-\frac23)+(\frac87-\frac43-10).$,12: Tính: $A=(8-\frac94+\frac27)-(-6-\frac37+\frac54)-(3+\frac24-\frac97).$,13: Tính: $A=(7+\frac75-\frac23)-(4+\frac45+\frac38)+(3-\frac35+\frac23+\frac38).$,14: Tính $:(\frac1{23};3;1)+$,15: Tính: $A=\frac13-\frac34+\frac35+\frac1{2007}-\frac1{36}+\frac1{15}-\frac29.$,:Lương Thị Huế

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Bài 7:

$$A=7+\left(\frac{7}{12}-\frac{1}{2}+3\right)-\left(\frac{1}{12}+5\right)$$

$$=7+\left(\frac{7}{12}-\frac{6}{12}+\frac{36}{12}\right)-\left(\frac{1}{12}+\frac{60}{12}\right)$$

$$=7+\frac{37}{12}-\frac{61}{12}$$

$$=7-\frac{24}{12}$$

$$=5$$

Bài 8:

$$A=-\frac{1}{4}+\frac{7}{33}-\frac{5}{3}-\left(-\frac{15}{12}+\frac{6}{11}-\frac{68}{49}\right)$$

$$=-\frac{1}{4}+\frac{7}{33}-\frac{5}{3}-\left(-\frac{5}{4}+\frac{6}{11}-\frac{68}{49}\right)$$

$$=\left(-\frac{1}{4}+\frac{5}{4}\right)+\left(\frac{7}{33}-\frac{6}{11}\right)-\frac{5}{3}+\frac{68}{49}$$

$$=1-\frac{1}{33}-\frac{5}{3}+\frac{68}{49}$$

$$=1-\frac{6}{3}+\frac{68}{49}$$

$$=-1+\frac{68}{49}$$

$$=\frac{19}{49}$$

Bài 9:

$$\left(3-\frac{1}{4}+\frac{2}{3}\right)-\left(5-\frac{1}{3}-\frac{6}{5}\right)-\left(6-\frac{7}{4}+\frac{3}{2}\right)$$

$$=\left(3-5-6\right)+\left(-\frac{1}{4}+\frac{7}{4}\right)+\left(\frac{2}{3}+\frac{1}{3}\right)+\frac{6}{5}-\frac{3}{2}$$

$$=-8+\frac{6}{4}+1+\frac{6}{5}-\frac{3}{2}$$

$$=\left(-8+1\right)+\left(\frac{3}{2}-\frac{3}{2}\right)+\frac{6}{5}$$

$$=-7+\frac{6}{5}$$

$$=-\frac{29}{5}$$

Bài 10:

$$\left(6-\frac{2}{3}+\frac{1}{2}\right)-\left(5+\frac{5}{3}-\frac{3}{2}\right)-\left(3-\frac{7}{3}+\frac{5}{2}\right)$$

$$=\left(6-5-3\right)+\left(-\frac{2}{3}-\frac{5}{3}+\frac{7}{3}\right)+\left(\frac{1}{2}+\frac{3}{2}-\frac{5}{2}\right)$$

$$=-2-\frac{1}{2}$$

$$=-\frac{5}{2}$$

Bài 11:

$$A=\left(\frac{5}{3}-\frac{3}{7}+9\right)-\left(2+\frac{5}{7}-\frac{2}{3}\right)+\left(\frac{8}{7}-\frac{4}{3}-10\right)$$

$$=\left(\frac{5}{3}+\frac{2}{3}-\frac{4}{3}\right)+\left(-\frac{3}{7}-\frac{5}{7}+\frac{8}{7}\right)+\left(9-2-10\right)$$

$$=\frac{3}{3}-3$$

$$=-2$$

Bài 12:

$$A=\left(8-\frac{9}{4}+\frac{2}{7}\right)-\left(-6-\frac{3}{7}+\frac{5}{4}\right)-\left(3+\frac{2}{4}-\frac{9}{7}\right)$$

$$=\left(8+6-3\right)+\left(-\frac{9}{4}-\frac{5}{4}-\frac{2}{4}\right)+\left(\frac{2}{7}+\frac{3}{7}+\frac{9}{7}\right)$$

$$=11-\frac{16}{4}+\frac{14}{7}$$

$$=11-4+2$$

$$=9$$

Bài 13:

$$A=\left(7+\frac{7}{5}-\frac{2}{3}\right)-\left(4+\frac{4}{5}+\frac{3}{8}\right)+\left(3-\frac{3}{5}+\frac{2}{3}+\frac{3}{8}\right)$$

$$=\left(7-4+3\right)+\left(\frac{7}{5}-\frac{4}{5}-\frac{3}{5}\right)+\left(-\frac{2}{3}+\frac{2}{3}\right)+\left(-\frac{3}{8}+\frac{3}{8}\right)$$

$$=6$$

Bài 15:

$$A=\frac{1}{3}-\frac{3}{4}+\frac{3}{5}+\frac{1}{2007}-\frac{1}{36}+\frac{1}{15}-\frac{2}{9}$$

$$=\left(\frac{1}{3}+\frac{1}{15}\right)+\left(-\frac{1}{36}-\frac{2}{9}\right)+\left(\frac{3}{5}-\frac{3}{4}\right)+\frac{1}{2007}$$

$$=\frac{2}{5}-\frac{1}{4}-\frac{3}{20}+\frac{1}{2007}$$

$$=0+\frac{1}{2007}$$

$$=\frac{1}{2007}$$.