Mr Atkins wrote some homework questions for his class to practise order of opera- tions. One of the questions was 2 + 3 × (4 + 3), with answer 23. However, one of his students just worked from left to right and ignored the brackets, writing 2 + 3 = 5, 5 × 4 = 20, 20 + 3 = 23, the correct answer. Mr Atkins thought that this was fascinating, so he tried to come up with another question where working left to right gave the right answer. He tried 5 + 4×(7 + ). What number should he put in the box?
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Australian Mathematics Competition 2020 - Junior (2020)
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