It took Sir Patrick Vallance, the chief scientific adviser, Dominic Cummings, Johnson’s chief adviser, and several messages to explain to the prime minister that he’d failed to grasp the numbers correctly.
Article source: https://www.huffingtonpost.co.uk/entry/boris-johnson-mocked-for-failing-to-grasp-basic-maths-during-pandemic_uk_63fe4fdae4b0cab1fa31bb0c