Is that calculation error really just a 'careless mistake'?

I often hear parents say, 'My child can do the calculations, but they make careless mistakes whenever the equations get long.
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Sindh plans to multiply urban property tax base under World Bank-backed program

The Sindh Property Revenues Enhancement Program, or SPREP, would provide $110 million through a Program-for-Results component and $40 million through Investment Project Financing. The KARACHI: The ...