Using Seven Digits To Get 40

Activities

Write the seven digits from 1 to 7 one after the other:

1 2 3 4 5 6 7.
It's easy to connect them by the plus and minus signs to obtain 40, e.g.

12 + 34 - 5 + 6 - 7 = 40.
Try and find another combination of these digits that would yield 55.

There are three solutions:

123 + 4 - 5 - 67 = 55;
1 - 2 - 3 - 4 + 56 + 7 = 55;
12 - 3 + 45 - 6 + 7 = 55.

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Source: Numeracy Counts !, Anita Rampal, R Ramanujam and L S Saraswati, N L R C, LBS National Academy of Administration, Mussoorie.