Tens and ones

Tens and ones: what children learn

In the game, children balance the scales by partitioning, such as 47 = 40 + ?. The Quick quiz asks two kinds of question: 'What is the value of the 4 in 47?' and '47 = ? tens and 7 ones'. Both check that children see a two-digit number as tens and ones, not just two digits side by side. Solid place value is what makes adding, subtracting and comparing bigger numbers possible.

Supports part of Common Core 1.NBT.B.2. This focused game does not cover the entire standard.

Common Core connection: 1.NBT.B.2. This is focused practice for part of the standard.

How to play

Make both sides of the scales equal. Tap the weight that fills the gap, or press 1 to 4. Each game has 8 questions and no timer. If a weight doesn't balance, the scales tip towards the heavier side and you get one more try. You get a point for each one balanced first time. For a quicker go, choose Quick quiz: 10 multiple-choice questions in 100 seconds (choose Relaxed for more time).

Step by step

1. Make the number with objects. Use bundles of 10 straws, base-10 sticks or dimes for tens, and single items or pennies for ones. 47 is 4 bundles of ten and 7 single straws.
2. Read the digits by place. The left digit tells you how many tens. The right digit tells you how many ones.
3. Say the value, not just the digit. The 4 in 47 is worth 40, because it means 4 tens. Saying 'forty' rather than 'four' builds the habit.
4. Partition in different ways. 47 = 40 + 7, but also 47 = 30 + 17. Being able to split numbers flexibly helps with subtraction later.

Worked examples

Common mistakes and how to fix them

• Saying the 4 in 47 is worth 4. Ask 'four what?' The answer is four tens, which is 40.
• Muddling teen numbers, such as writing 71 for seventeen. Teen numbers say the ones first. Use a place value chart and build seventeen as 1 ten and 7 ones.
• Thinking 0 means nothing, so 30 is 'just 3'. Show that 0 holds the ones place: 30 is 3 tens and no ones.

Activities to try at home

• Use dimes and pennies: make 36¢ in as few coins as possible.
• Look at house numbers or bus numbers and ask what each digit is worth.
• Swap the digits of a number (47 and 74): which is bigger and why?

Ideas for the classroom

• Use place value charts and arrow cards (40 and 7 overlapping to make 47).
• Play 'make the biggest number' with two digit cards.
• Ask students to partition the same number in three different ways.

Free printable game and worksheet

The free printable starts with a game sheet, such as a color-by-answer picture, an answer maze or a secret-code joke, followed by a worksheet. Both use the same checked questions as the online game, and the answers are on the last page. Print it, or save it as a PDF from your browser’s print menu.

Open the free printable game and worksheet

Frequently asked questions

Related topics

• Hundreds, tens and ones (Grade 2 math) – Quiz race on the value of each digit in a three-digit number. Free Grade 2 math game.
• Ordering numbers to 100 (Grade 1 math) – Put numbers to 100 in order, smallest or largest first. Free Grade 1 math game.
• 1 more and 1 less (Grade 1 math) – Quick-fire Grade 1 math game: find 1 more and 1 less than numbers up to 100.
• Numbers on a number line to 20 (Grade 2 math) – Place numbers to 20 on a number line. Free Grade 2 math game that builds number sense.
• 10 or 100 more or less (Grade 2 math) – Find 10 or 100 more or less than three-digit numbers, including across hundreds. Free Grade 2 math game.
• Roman numerals to 100 (Grade 3 math) – Match Roman numerals I to C with their values. Free Grade 3 math game.

Back to Grade 1 math