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CK-12 Foundation
Ck 12: Arithmetic: Estimation of Whole Number
[Free Registration/Login may be required to access all resource tools.] Round whole numbers in order to estimate sums and differences.
CK-12 Foundation
Ck 12: Arithmetic: Front End Estimation Grade 6
[Free Registration/Login may be required to access all resource tools.] Estimate sums and differences of decimals using front-end estimation.
CK-12 Foundation
Ck 12: Arithmetic: Decimal Addition
[Free Registration/Login may be required to access all resource tools.] Add decimals with and without rounding
CK-12 Foundation
Ck 12: Arithmetic: Decimal Addition Using Front End Estimation
[Free Registration/Login may be required to access all resource tools.] Use front-end estimation to estimate decimal sums