Dev thinks of a whole number.He multiplies it by 4.He rounds his answer to the nearest 10.The result is 50. Write all the possible numbers that Dev could have started with.
There is only one answer, which is 4×12. Because 4×12=48, then rounded is 50, but 4×11=44 and can't be rounded to 50, and 4×13=52 and can't be rounded to 50.
