If you're teaching kids to round 2 and 3-digit numbers to the nearest ten, take a look at this page. It has a Scoot game, lots of worksheets, and rounding charts.
(examples: 75 rounds to 80; 167 rounds to 170)
On this worksheets, pupils will round numbers to the nearest hundred. There's also a section for rounding to nearest ten and hundred (mixed).
(examples: 345 rounds to 300; 1,677 rounds to 1,700)
This section has a few printables on rounding to the nearest thousand.
(example: 5,765 rounds to 6,000)
Round decimals to the nearest tenth, hundredth, thousandth, and/or whole number.
(example: 2.67 rounds to 3)
Round money amounts to the nearest dollar. There's a math riddle activity, and practice worksheets.
(example: $6.71 rounds to $7.00)
Round each amount up to the next dollar to determine how many bills to give a cashier.
(example: $4.12 rounds up to $5.00)
Super Teacher Worksheets has a HUGE collection of place value worksheets. Use these resources for teaching kids about comparing and ordering numbers, place value blocks, expanded notation, and digit values.