1.NBT.C.4: Add within 100 using place value; sometimes a ten is made

Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings, and strategies based on place value, properties of operations, and/or the…Common Core State Standards for Mathematics, as adopted in the Massachusetts Curriculum Framework for Mathematics (2017), Grade 1.

Play the game: Place by PlaceStep 49 of the ColorMyMath curriculum · free, no sign-up →

How ColorMyMath teaches it

Past nine, color tells you which place a digit lives in. A ten is a triangle of ten dots; the number of triangles is the tens digit, so 34 is three triangles and four loose green dots.

Every page is free and open — nothing to install, no account, and it works on a phone or a classroom board. Every number has its own color: 1 red, 2 orange, 3 yellow, 4 green, 5 blue, 6 purple, 7 brown, 8 pink, 9 cyan, and a number is that many colored dots.

Where it sits in the curriculum

• Step 49Two-digit addition with easy facts
• Step 53Two-digit addition with hard facts — carrying

More Grade 1 standards in Number and Operations in Base Ten

• 1.NBT.A.1Count to 120 starting from any number; read and write those numbers
• 1.NBT.A.2The two digits of a two-digit number are tens and ones
• 1.NBT.A.3Compare two-digit numbers with >, = and <
• 1.NBT.C.5Find 10 more and 10 less than a two-digit number in your head
• 1.NBT.C.6Subtract multiples of 10 from multiples of 10

ColorMyMath · getridoftheteacher.com · every number has its own color, and a number is that many colored dots. Matching a game to a standard is a judgement call; the official text is at doe.mass.edu.