Breaking Apart Addends

Mental Math · Axiom Academy

Keep one number whole and break the other into easy bites — and pick the bites so you land on a friendly round number along the way. 1. Keep One Whole, Break the Other Take 56 + 37 . Leave 56 sitting there as your anchor and break the 37 into friendlier pieces: 30 + 7 . Add the big piece first — 56 + 30 is 86 — then the small one — 86 + 7 is 93. The 56 never moves; the 37 arrives in easy bites. One number stays whole; the other lands in bites 2. Bridge Through a Friendly Number Here is the powerful move. Same 56 + 37 , but split the 37 as 30 + 4 + 3 . Add the 30 to reach 86, then add just 4 to land on 90 — a round, friendly number — and finish with the last 3 : 90 + 3 is 93. That little pause on 90 is what makes the rest effortless. The middle bite is chosen to hit a round 90 For 73 + 19 , anchor the 73 and split the 19 as 7 + 12 : the 7 rounds 73 up to 80 , then 80 + 12 is 92 — one clean hop through 80. 3. Bite Just Enough to Round Up First When your anchor is already close to a round number, bridge first . Take 48 + 26 : 48 only needs 2 to reach 50 , so break the 26 as 2 + 24 . Add the 2 to round up — 48 + 2 is 50 — then drop in the rest — 50 + 24 is 74. One tiny bite buys you a friendly 50. A small first bite rounds the anchor up to 50 For 65 + 28 , the 65 needs 5 to reach 70 , so split the 28 as 5 + 23 : 65 + 5 is 70, then 70 + 23 is 93. You can now keep one number whole and feed the other in as easy bites — steering through a friendly round number whenever one is close.

This is the written version of the interactive lesson above. See the full Mental Math course.