# Do we just add a zero at the end?

Creating number sense is something students struggle with throughout their elementary school career – I know that I definitely wrestled with this as a child. We operate on a base ten number system, but we often fail to develop the conceptual understanding behind operating on a ‘base ten’ number system. Many teachers will say “just add a zero at the end of the number when you multiply by 10” (I was taught this way when I was in school). To a certain extent, this is true. This simple trick does make life easier when teaching, but what many don’t realize is the real disservice this does to our students. Students are led to develop a weak understanding of our number system and a poor mathematical foundation.

Why do we “just add a zero” at the end of a number?

Because we multiply by 10!

It’s not a bad trick to teach our students to “add a zero” at the end of a number when multiplying by ten, but make it a habit of telling students that we do it because we are multiplying by ten. Tricks and strategies are ‘convenient’ (especially for those students who really don’t get it), but we need to remember to always explain the logic behind them.

Quick and easy activities to reinforce our base ten system

## Speed Exchange

Before: Ask the question using base ten blocks, “How many ones do you need to make a ten?” Allow students time to explore and have a quick class discussion. Make sure to physically stack the ones on top of a ten to show how 10 ones has the same value as 1 ten.

Activity: Pair students up with some base ten blocks. One partner will be in charge of gathering 10 one blocks while the other partner is listening, watching, and regrouping the ones for tens. Set the timer for a minute. When the timer starts, partner A gathers and counts out 10 one blocks. Partner A needs to say, “I have 10 ones that I want to regroup for 1 ten,” before Partner B hands them a ten. The goal is to gather as many base ten blocks as possible before the timer stops. The partners will switch roles after the first round.

“I have 10 ones that I want to regroup for 1 ten” or “I have 10 ones give me a ten”

**Do a round for regrouping 10 tens for 1 hundred! See if the students can figure out how many tens they need for 1 hundred

After: Students can discuss with one another what they learned from this short activity. Help them grasp the concept of regrouping – grouping by tens to get the next place value.

– Reinforces our base ten system using the physical ‘regrouping’ of 10 ones for 1 ten.
– Students quickly memorize the vocabulary by verbalizing the statement many times.
– Quick, easy, and a fun competitive activity!

## Make the Number

Challenge the students to show different ways to make a certain number using their base ten blocks!

For example “Show me different ways you can make 200 with base ten blocks”

– Students have to problem solve as they think of different ways to show one specific number.
– Reinforces that in our base ten system there are various ways to represent a number.
– Students can learn from their peers through gallery walks and discussions.
– Quick and easy