Question

Find the values of the letters in the following and give reasons for the steps involved. [2 marks]
$2AB$
$\underset{–}{+AB1}$
$\underset{–}{B18}$

Answer 1

Unit place of B + 1 is 8
So, B = 7
On putting B = 7,
$\Rightarrow$ 7 + 1 = 8
Now unit digit of A + B is 1 and B = 7 So A = 4
Now A = 4, then 4 + 7 = 11
Putting 1 at tens place and carry over 1, we get
2 + 4 + 1 = 7
Hence, A = 4 and B =7