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Grade 5 Math · Level 1, Place Value & Powers of 10

Round Decimals

How the lesson starts: Round Decimals

1. Gus hits the trail

   Meet Gus the mountain goat! He's hiking a trail, and he's at 6.47 kilometers. The signposts are only at every tenth: 6.4, 6.5, and so on. Gus wants to hop to the nearest signpost. Rounding tells him which one!

2. Hop to the nearest

   Here's Gus's stretch, from 6.4 to 6.5. The halfway mark is 6.45. Gus is at 6.47, past halfway, so he is closer to 6.5. The goat rule: peek at the next digit. 0 to 4 stays down, 5 to 9 rounds up.

3. Round to the hundredth

   Tilly is at 3.8362. Round to the nearest hundredth. Find the hundredths digit: 3. Peek at the very next digit: 6. Six means round up, so the 3 becomes 4. Drop the rest: 3.84. Watch out: peek one step right, not at the last digit!