About this game

Add two numbers (sum up to 10)

Add two numbers (sum up to 10): a free Grade 1 math game for ages 6-7. Each round draws 8 questions; instructions are read aloud and every answer is checked and explained.

How it plays and why it helps

Give a child 1 + 9 and watch nine fingers go up one at a time. Add two numbers (sum up to 10) is a Grade 1 keypad game with 65 sums, from 0 + 1 to 5 + 5. Eight make a round. The instruction is read aloud, your child types the total, and every answer is checked and explained the same way: start from 1, count on 9.

Counting on, starting from the first number instead of from one, is the bridge between counting all and knowing facts. The explanations model it on every card. Turning the sum around helps too: 1 + 9 and 9 + 1 are both in the bank, and counting on 1 from 9 is far quicker than counting on 9 from 1.

One classic slip comes with counting on: saying the starting number again. For 4 + 3, a child counts four, five, six and types 6. Ask, "Where do we start, and where does the first finger go?" Praise the method: "You started from the big number."

Aligned with

  • 1.NBT.C.4 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 relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
  • 1.OA.C.6 Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 - 4 = 13 - 3 - 1 = 10 - 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 - 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).

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