Excerpted from "The Grapes of Math: How Life Reflects Numbers and Numbers Reflect Life." Numbers were invented to describe precise amounts: three teeth, seven days, twelve goats. When quantities are ...

When you do not need to speak or write about exact quantities or measures, learning to round numbers to 10, 100 or 1,000 can be useful. It can make calculations easier and it also helps when you are ...

Use rounded values to estimate close the answer to a calculation. This is a useful non-calculator skill. Refresh your knowledge with these guides on rounding and significant figures. Rounding to ...

Use place value cards to practice rounding numbers to the nearest ten and hundred. Warm up with a Mystery Math Mistake to hunt for the mistake made counting up on the number line. Use place value ...