diff --git a/todo.txt b/todo.txt
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+- Implement GpuRational struct to extend GpuUInt128 range. Avoid extending method calls stack. Instead prefer code duplication for a better performance. Create unit tests for it and benchmarks to compare against GpuUInt128. GpuRational should work in a similar way to ERational to avoid excessive memory usage. You have many methods available in GpuUInt128 and GpuUInt128Extensions. Many are also similar to UInt128Extensions and/or ULongExtensions.
 - Extend the GPU numeric type probe to cover proposed custom types such as GpuUInt256 and GpuUInt512 once their definitions are available so we can plan the wide-order heuristics on the device.