Bài tập ôn hè Toán 4 lên lớp 5 Dạng 5: Các dạng toán tìm x có đáp án

58 564 – x = 2354

x = 58 564 – 2354

x =  56 210

45 451 + x = 65 153

x = 65 153 – 45 451

x = 19 702  

x – 2342 = 38 371

x = 38 371 + 2342

x = 40 713

19 488 : x = 348

x = 19 488 : 348

x = 56

45 478 – x = 3945

x = 45 478 – 3945

x = 41 533

x × 42 = 15 792

x = 15 792 : 42

x = 376

2852 + x = 33 164

x = 33 164 – 2852

x = 30 312

x + 5376 = 1548 × 4

x + 5376 = 6192

x = 6192 – 5376

x = 816

x – 5678 = 12 483 × 4

x – 5678 = 49 932

x = 49 932 + 5678

x = 55 610

(x + 5687) : 7 = 3542 + 18 754

(x + 5687) : 7 = 22 296

x + 5687 = 22 296 × 7

x + 5687 = 156 072

x = 156 072 – 5687

x = 150 385

758 293 – x = 12 547 + 325 487

758 293 – x = 338 034

x = 758 293 – 338 034

x = 420 259

(x – 3256) + 2589 = 12 587 – 2658

(x – 3256) + 2589 = 9929

x – 3256 = 9929 – 2589

x – 3256 = 7340

x = 7340 + 3256

x = 10 596

125 879 – (x – 2597) – 5879 = 52 369

120 000 – (x – 2597) = 52 369

x – 2597 = 120 000 – 52 369

x – 2597 = 67 631

x = 67 631 + 2597

x = 70 228

x × 274 – 256 × x = 5130

 x × (274 – 256) = 5130

18 × x = 5130

x = 5130 : 18

x = 285

x × 18 × 19 = 43 434

342 × x = 43 434

x = 43 434 : 342

x = 127

2006 : x + 1955 = 2014

2006 : x = 2014 – 1955

2006 : x = 59

x = 2006 : 59

x = 34

x × 35 – 35 = 1225

x × 35 = 1225 + 35

x × 35 = 1260

x = 1260 : 35

x = 36

981 × (x + 189) = 185 409

x + 189 = 185 409 : 981

x + 189 = 189

x = 189 – 189

x = 0

216 : x – 117 : x + 18 : x = 9

(216 – 117 + 18) : x = 9

117 : x = 9

x = 117 : 9

x = 13

256 × x – 215 × x = 29 643

(256 – 215) × x = 29 643

41 × x = 29 643

x = 29 643 : 41

x = 723

$\frac{2}{3}+x=\frac{5}{6}$

$x=\frac{5}{6}-\frac{2}{3}$

$x=\frac{5-4}{6}$

$x=\frac{1}{6}$

$x-\frac{1}{5}=\frac{4}{7}$

$x=\frac{4}{7}+\frac{1}{5}$

$x=\frac{20}{35}+\frac{7}{35}$

$x=\frac{27}{35}$

$\frac{5}{6}-x=\frac{1}{3}$

$x=\frac{5}{6}-\frac{1}{3}$

$x=\frac{3}{6}$

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

$\frac{1}{3}\times x=\frac{1}{8}$

$x=\frac{1}{8}:\frac{1}{3}$

$x=\frac{1}{8}\times 3$

$x=\frac{3}{8}$

$x\times \frac{6}{5}=\frac{7}{2}$

$x=\frac{7}{2}:\frac{6}{5}$

$x=\frac{7}{2}\times \frac{5}{6}$

$x=\frac{35}{12}$

$x:\frac{8}{9}=\frac{27}{32}$

$x=\frac{27}{32}\times \frac{8}{9}$

$x=\frac{3}{4}$

$\frac{25}{8}:x=\frac{5}{16}$

$x=\frac{25}{8}:\frac{5}{16}$

$x=\frac{25}{8}\times \frac{16}{5}$

$x=\frac{5\times 5\times 2\times 8}{8\times 5}$

x = 10

$x+\frac{7}{15}=\frac{6}{5}$

$x=\frac{6}{5}-\frac{7}{15}$

$x=\frac{18}{15}-\frac{7}{15}$

$x=\frac{1}{15}$

$x:\frac{28}{49}=\frac{7}{2}$

$x=\frac{7\times 28}{2\times 49}$

$x=\frac{7\times 7\times 2\times 2}{2\times 7\times 7}$

x = 2

$6\times x=\frac{5}{8}:\frac{3}{4}$

$6\times x=\frac{5}{8}\times \frac{4}{3}$

$6\times x=\frac{5}{6}$

$x=\frac{5}{6}:6$

$x=\frac{5}{6\times 6}$

$x=\frac{5}{36}$

$x:\frac{7}{9}=4-\frac{23}{8}$

$x:\frac{7}{9}=\frac{4\times 8-23}{8}=\frac{1}{8}$

$x=\frac{1}{8}\times \frac{7}{9}=\frac{7}{72}$

$x+\frac{3}{4}=\frac{5}{3}$

$x=\frac{5}{3}-\frac{3}{4}$

$x=\frac{20}{12}-\frac{9}{12}$

$x=\frac{11}{12}$

$x-\frac{2}{3}=\frac{7}{2}$

$x=\frac{7}{2}+\frac{2}{3}$

$x=\frac{21}{6}+\frac{4}{6}$

$x=\frac{25}{6}$

$x:\frac{3}{4}=\frac{7}{8}-\frac{1}{4}$

$x:\frac{3}{4}=\frac{7}{8}-\frac{2}{8}$

$x:\frac{3}{4}=\frac{5}{8}$

$x=\frac{5}{8}\times \frac{3}{4}$

$x=\frac{15}{32}$

$x\times \frac{3}{5}+x\times \frac{1}{2}=\frac{11}{15}$

$x\times \left(\frac{3}{5}+\frac{1}{2}\right)=\frac{11}{15}$

$\left(\frac{6}{10}+\frac{5}{10}\right)\times x=\frac{11}{15}$

$\frac{11}{10}\times x=\frac{11}{15}$

$x=\frac{11}{15}:\frac{11}{10}$

$x=\frac{11}{15}\times \frac{10}{11}$

$x=\frac{2}{3}$

$x\times \frac{2}{5}-\frac{1}{2}\times \frac{3}{5}=\frac{3}{10}$

$x\times \frac{2}{5}-\frac{3}{10}=\frac{3}{10}$

$x\times \frac{2}{5}=\frac{3}{10}+\frac{3}{10}$

$x\times \frac{2}{5}=\frac{3}{5}$

$x=\frac{3}{5}:\frac{2}{5}$

$x=\frac{3}{5}\times \frac{5}{2}$

$x=\frac{3}{2}$

$\frac{7}{20}-\frac{1}{2}:x=\frac{3}{20}$

$\frac{1}{2}:x=\frac{7}{20}-\frac{3}{20}$

$\frac{1}{2}:x=\frac{4}{20}$

$\frac{1}{2}:x=\frac{1}{5}$

$x=\frac{1}{2}:\frac{1}{5}$

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

$\frac{7}{9}:\left(x-\frac{4}{9}\right)=\frac{1}{2}$

$x-\frac{4}{9}=\frac{7}{9}:\frac{1}{2}$

$x-\frac{4}{9}=\frac{14}{9}$

$x=\frac{14}{9}+\frac{4}{9}$

$x=\frac{18}{9}$

x = 2

$\frac{8}{x}+\frac{1}{5}=\frac{2}{5}+\frac{1}{3}$ (x là số tự nhiên khác 0)

$\frac{8}{x}+\frac{1}{5}=\frac{6}{15}+\frac{5}{15}$

$\frac{8}{x}+\frac{1}{5}=\frac{11}{15}$

$\frac{8}{x}=\frac{11}{15}-\frac{1}{5}$

$\frac{8}{x}=\frac{8}{15}$

x = 15 (thoả mãn)

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

$\frac{1}{4}+x=\frac{6}{7}:\frac{2}{3}$

$\frac{1}{4}+x=\frac{6}{7}\times \frac{3}{2}$

$\frac{1}{4}+x=\frac{18}{14}$

$x=\frac{18}{14}-\frac{1}{4}$

$x=\frac{36}{28}-\frac{7}{28}$

$x=\frac{29}{28}$

$\left(x-\frac{3}{5}\right):\frac{1}{5}=\frac{5}{8}$

$x-\frac{3}{5}=\frac{5}{8}\times \frac{1}{5}$

$x-\frac{3}{5}=\frac{1}{8}$

$x=\frac{1}{8}+\frac{3}{5}$

$x=\frac{5}{40}+\frac{24}{40}$

$x=\frac{29}{40}$

$\left(x+\frac{5}{9}\right)\times \frac{2}{3}=\frac{2}{5}$

$x+\frac{5}{9}=\frac{2}{5}:\frac{2}{3}$

$x+\frac{5}{9}=\frac{2}{5}\times \frac{3}{2}$

$x+\frac{5}{9}=\frac{3}{5}$

$x=\frac{3}{5}-\frac{5}{9}$

$x=\frac{27}{45}-\frac{25}{45}$

$x=\frac{2}{45}$

$\frac{3}{5}\times x-\frac{3}{2}=\frac{5}{6}$

$\frac{3}{5}\times x=\frac{5}{6}+\frac{3}{2}$

$\frac{3}{5}\times x=\frac{5}{6}+\frac{9}{6}$

$\frac{3}{5}\times x=\frac{14}{6}$

$\frac{3}{5}\times x=\frac{7}{3}$

$x=\frac{7}{3}:\frac{3}{5}$

$x=\frac{7}{3}\times \frac{5}{3}$

$x=\frac{35}{9}$

$x-\frac{4}{9}=\frac{3}{7}:\frac{9}{14}$

$x-\frac{4}{9}=\frac{3}{7}\times \frac{14}{9}$

$x-\frac{4}{9}=\frac{3\times 2\times 7}{7\times 3\times 3}$

$x-\frac{4}{9}=\frac{2}{3}$

$x=\frac{2}{3}+\frac{4}{9}$

$x=\frac{6}{9}+\frac{4}{9}$

$x=\frac{10}{9}$