The NumberSense cast
Each friend shows you one idea by how they act. Meet them all and see how the ideas fit together.
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Estimator Ernie Confidently approximate; the first-guess advocate -
Pivot Pia Deceptively casual question-flipper; reframes the prompt -
Ratio Rio Per-something specialist; rate thinker -
Splitter Sasha Make-10 and place-value specialist; benchmark builder -
Nudge Nora Compensation — nudge a number to a friendly round one, do the easy math, then give back exactly what you borrowed. -
Doubler Della Doubling and halving — to multiply, double one number and halve the other; the product stays the same while one side gets friendlier. -
Landmark Lena Benchmark numbers — judge any number by how it sits next to friendly landmarks like 0, a half, 10, 50, and 100. -
Factor Fiona Factors and multiples — every number is built from smaller numbers multiplied together, and seeing the building blocks makes hard arithmetic come apart. -
Gap Gus Constant difference — subtraction is the gap between two numbers; slide both the same amount and the gap stays the same, so you can land on friendly numbers. -
Bridge Bao Derived facts — reach a fact you don't know by taking one short step out from a fact you do.