Bài 1:
a. X + 173738 = 892381
X = 892381 - 173738
= 718643
b. X - 618722 = 17894
X = 17894 + 618722
= 636616
c. X : 7 = 183
X = 183 × 7
= 1281
d. 13607 : X = 8
X = 13607 ÷ 8
= 1700,875
e. X × 4 = 51856
X = 51856 ÷ 4
= 12964
g. 9 × X = 40095
X = 40095 ÷ 9
= 4455
h. (X + 35) × 6 = 13272
X + 35 = 13272 ÷ 6
= 2212
X = 2212 - 35
= 2177
i. 57316 : (X - 825) = 4
X - 825 = 57316 ÷ 4
= 14329
X = 14329 + 825
= 15154
Bài 2:
a. 25 × 5 × 4 × 3
= (25 × 5) × (4 × 3)
= 125 × 12
= 1500
b. 236 × 20 - 36 × 20
= (236 - 36) × 20
= 200 × 20
= 4000
c. 785 × 214 + 215 × 214
= 785 × 214 + 215 × 214
= (785 + 215) × 214
= 1000 × 214
= 214000
d. (367 × 584 + 12345) × (3570 : 357 - 10)
= (367 × 584 + 12345) × (10 - 10)
= (367 × 584 + 12345) × 0
= 0