the number of pens in the school is 3450 to the nearest 10 what is the highest number of pens there could be in school

So we need to round to the nearest ten with the result being 3450. When rounding to the nearest 10 we look to the ones place. If the ones place is 5 or higher we round up to the next 10. So the highest we can go is 3454 which rounds down to 3450. If we would have gone 1 more higher to 3455 then it would have rounded up to 3460.

So the highest possible number of pens would be

3454.