问题1
3个
+ 2 5
——–
B 2
——–
解决方案：
A + 5 we get the unit digit as 2
if A = 7 , we get 7 + 5 = 12
The value of B = 1(carry) + 3 + 2 = 6
Hence the addition is
3 7
+ 2 5
——–
6 2
——–
Hence A = 7 and B = 6
问题2。
4个
+ 9 8
————
碳三
————
解决方案：
A + 8 we get the unit digit as 3
if A = 5, we get A + 8 = 13
The values of B and C = 1(carry) + 4 + 9 = 14
1 is taken as carry
Hence the addition is
4 5
+ 9 8
————
1 4 3
————
Hence A = 5, B = 4 and C = 1
问题3。
1个
设
————-
9个
——————
解决方案：
A x A = A if A = 1 or 6
For A = 1
1 x 1 = 1 which is not equal to 9
For A = 6
6 x 6 = 36
1 x 6 = 6
Hence the multiplication is
1 6
X 6
————-
9 6
————–
Hence A = 6
问题4。
甲乙
+ 3 7
——–
6个
——–
解决方案：
A + 3 = 6
A = 6 – 3 = 3 = 2 + 1(carry)
A = 2
B + 7 we get the unit digit as 2
if B = 5 we get 5 + 7 = 12
Hence the addition is
2 5
+ 3 7
——–
6 2
———
Hence A = 2 and B = 5
问题5
甲乙
X 3
————-
出租车
————-
解决方案：
B x 3 = B
B = 0
A x 3 = CA
if A = 5 then 5 x 3 = 15
and C = 1
Hence the multiplication is
5 0
X 3
————-
1 5 0
————-
Hence A = 5 , B = 0 and C = 1
问题6。
甲乙
5倍
————-
出租车
————-
解决方案：
B x 5 = B
B = 0 or 5
A x 5 = CA
if A = 5 then 5 x 5 = 25
and C = 2
Only possible when B = 0
Hence the multiplication is
5 0
X 5
————-
2 5 0
————-
Hence A = 5 , B = 0 and C = 2
问题7。
甲乙
×6
————
B B B
————
解决方案：
B x 6 = B
if B = 4
4 x 6 = 24
where 2 is carry
A x 6 = BB
if A = 7
7 x 6 = 42
Hence multiplication is
7 4
× 6
————
4 4 4
————-
Hence A = 7 and B = 4
问题8。
A 1
+ 1 B
–——–
B 0
–——–
解决方案：
1 + B we get unit digit as 0
if B = 9
1 + 9 = 10
where 1 is the carry
1(carry) + A + 1 = B = 9
A + 2 = 9
A = 9 – 2 = 7
Hence addition is
7 1
+ 1 9
———–
9 0
———–
Hence A = 7 and B = 9
问题9。
2 A B
+ A B 1
——————
B 1 8
——————
解决方案：
B + 1 we get the unit digit as 8
if B = 7
7 + 1 = 8
A + 7 we get the tens digit as 1
if A = 4
4 + 7 = 11
where 1 is the carry
1(carry) + 2 + 4 = 7
Hence addition is
2 4 7
+ 4 7 1
—————
7 1 8
—————-
Hence A = 4 and B = 7
问题10。
1 2 A
+ 6 A B
—————-
0 0
—————-
解决方案：
A + B = 9
if A = 8 and B =1
8 + 1 = 9
2 + A = 0
if A = 8
2 + 8 = 10
where 1 is the carry
1(carry) + 1 + 6 = A = 8
Hence the addition is
1 2 8
+ 6 8 1
—————-
8 0 9
—————-
Hence A = 8 and B = 1