About this game

Add in your head

Add in your head: a free Grade 1 math game for ages 6-7. Each round draws 5 questions; instructions are read aloud and every answer is checked and explained.

How it plays and why it helps

What is 8 + 7 when there is no pencil? Add in your head is a Grade 1 game of mental sums, from 3 + 4 up to 36 + 8. Each card is read aloud, your child works it out without writing, then taps the answer among four close numbers. Five sums make a round and every answer is checked.

Mental addition rests on known facts and on bridging ten: 8 + 7 is 8 + 2, then 5 more. The hint asks for exactly that, a way to add without writing every step. The later cards cross into the twenties, thirties and forties, where the same move does the work: 28 + 5 is 28 + 2, then 3.

When a sum crosses a ten, one choice sits ten below the answer: 12 for 14 + 8, 22 for 25 + 7. It is what you get when the new ten is lost along the way. Ask, "Did we pass a ten?" Then praise the bridge: "You made a ten first and it worked."

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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