1. If a brick weighs 9kg and half a brick then 9kg must be the other half and the brick weighs 18kg. So a brick and a half weighs 18 + 9 = 27kg

2. This is tricky but you can get started. Because the TY is not altered from FORTY to SIXTY we know EN + EN = 100 ie 50 + 50. Notice that the O changes to I and the F to S so both required a carry. To carry from the O column and not get a nought at the bottom remember N=0 we must have to have had a carry of two so T + T + R must be greater than 20, I = 1 and S is one more than F. Y can be anything so put in whatever letter is left (ie leave this until last!) We have done a lot of the work so with a bit of trial and error for T you will get:                  

        8  5  0  

        8  5  0

2  9  7  8  6

3  1  4  8  6

 

3. This problem looks beguilingly simple. You might try 541x32 = 17312 and then realise 531x 42 = 22302. Did you stop there? Think again … you can do better!