Another short week of warm-ups because of MLK, Jr. Day on Monday, but the ones we had this week are goodies! Read on and happy calculating! Please let me know how/if you use these in your classroom! Feel free to add your own warm-ups in the comments, too! 🙂
The unit we’re in right now is math is focusing on adding numbers within 100, and on using place value to do so in an efficient manner. My focus then, this week has been on how to create opportunities to think about tens in a meaningful way determine which strategies and models make sense in each situation. This one was just a great place to start our conversation for the week because it has so many answers.
We’ve been doing many problems around scenarios, and I wanted to see what they could do with straight numbers–especially related to place value. This was a great one to see what they know both about tens/ones, and what they know how to do with them. You can see that there are already many known strategies and models floating around that we can build from as we go forward. YAY!
We’ve been playing the 100s Game this week as we practice counting to 100 by different numbers. We’ve had lots of practice with counting to 100 by 5s and then 10s (really fast!), but then we practiced counting by 10s and NOT starting at 0. We used a deck of cards to decide what was our first number, then we went around and stopped at the number that was closest to 100 (for example, if we started with 6, then we’d say 6, 16, 26, 36, 46, 56, 66, 76, 86, 96). This warm up was similar to the game we’d been playing, only I wanted to see if they knew what to do when they went over 100, so asked them to go as high as they could. HA! Man…were those numbers high! One friend went all the way to 867 (and I think he only stopped because he ran out of time!), and many went to the 600s or so. As we discussed the problem and did it together, I quickly found out that they did indeed know the pattern of how it works when you get into the 100s. This will be so handy as we keep going, and many will modify their counting on strategy from numbers within 20 to counting on by 10s with numbers within 100.
This one was a true story about how I spent my evening last night! While it is really a problem to see what they can do with tens, it’s also the beginning of multiplicative thinking, as it’s also 8 X 20 or 20 X 8; either way, i want them to recognize that it’s 8 groups of 20, not 8 PLUS 20. Most did a SUPER job of this and had great thinking about how to figure it out. Several connected the 20 to counting by 2s, and some saw the 2 10s inside 20 and counted by 10s to get to 160. The best part was that NO ONE sat and did nothing. Everyone tried a strategy, and were willing even if they weren’t quite sure about the answer. I LOVE how gritty these kiddos are!
Our record of how to use 2s to figure out the answer. We made sure to highlight how those 2s can mean 2 10s and so 16 10s is 160. Then, just for fun, we figured out how many hours those minutes would be equal to: 2 hours and 40 minutes!